Please explain what you're actually doing Kennith.

import random
import os
import sys

words = [
    'lemon',
    'apple',
    'citrus',
    'cucumber',
    'melon',
    'orange',
    'carrot',
    'squash'
]
#Create a function that once called, it will clear the console window,
# to make the game look better
def clear():
    #Inside the "os" module there's a variable called "os" which has an attribute called name in it, you acces
    #attribute with the dot notation syntax; os.name
    #We are just using this code to check if the user is on a windows machine, or mac / linux
    #In case of windows, the value of os.name will 'nt' so we return os.system('cls')
    #We need to check for the OS on the users PC because the commands we need to execute are different.
    #On Windows, you have the command line (cmd.exe) which if you enter "cls" will clear the screen
    #On Mac fx. we have the terminal, which if you enter "clear", it will clear the screen.
    #That's the job of this function
    if os.name == 'nt':
        os.system('cls')
    else:
        os.system('clear')

# This is the "UI" of the game ( Very primitive yes :) )
#We declare a function, which has 3 parameters (badGuesses, goodGuesses, secretWord)
def draw(badGuesses, goodGuesses, secretWord):
    # We call the function clear() we just created
    clear()
    # print some UI stuff, I'm confident you understand this :)
    print('Strikes: {}/7'.format(len(badGuesses)))
    print()

    #We iterate over each letter in badGuesses (Which is a list of letters the users have guessed wrong)
    for letter in badGuesses:
        #We print each of the letters, one at a time, on each iteration of the for loop,
        #The end=" " is also some UI stuff, if we didn't include it, the print() functions default
        #value is "\n" which means "print something and jump to the next line", but we don't want this
        #new line that python gives us by default, so we need to change the default value, in this case
        #we give it a value of a space character " "
        print(letter, end=" ")
        #Now you know that "\n" is a "New line character" :) so I'm sure you can guess what the next line
        #will print, if you said 2 new lines, you would be correct! :)
    print("\n\n")

    #We iterate over each letter in the secretWord list, which is the full word that the computer
    #pulled from our words list
    for letter in secretWord:
        #We check to see if the letter of each iteration, is inside the goodGuesses list, if it is,
        #jump inside the if condition, and print this letter and the end='' here just means, don't
        # jump to a new line after you have printed this
        if letter in goodGuesses:
            print(letter, end='')
        else:
            #This is also purely UI stuff, if the letter was NOT inside goodGuesses list, this code will run
            #and it will print a _ , which will just make it more visually appealing I guess, the _ will
            # be replaced by a letter essentially, once the user has guessed a correct letter, and the if condition
            # above will run instead of the else condition :)
            print('_', end='')
    #Just prints a new line, UI Stuff
    print("")

# We need to get a guess from the user, and that is this functions job.

def getGuess(badGuesses, goodGuesses):

    #We use a while loop here, just to create an infinite loop
    #We do that becuase if the user enters some invalid input, they will keep being reprompted for a new input
    while True:
        #Stores the users input and the .lower() method, just changes the value of the input to lower capitalization
        #to make it easier to compare against. So we don't need to say
        """"
            if guess == "Y":
                # some code
            elif guess == "y":

        """
        #It just makes it easier.

        guess = input("Guess a letter: ").lower()

        #Here's where we check if the user entered some invalid input
        #if the length of guess, is not equal to 1, (that is if it's more than one letter)
        #Then print "You can only guess a single letter!", and then we will jump back up to the beginning of the
        #while loop, and ask for a new input
        if len(guess) != 1:
            print("You can only guess a single letter!")

        # else, if the value of guess, is already inside of badGuesses or goodGuesses,
        #That must mean the user had already guessed that.
        elif guess in badGuesses or guess in goodGuesses:
            print("You've already guess taht letter!")

        #The .isalpha() method checks if the value of guess is an alpha numerical value
        # else if the value of guess is NOT an alpha numerical value, print " You can only guess letters!"
        elif not guess.isalpha():
            print("You can only guess letters!")
        #If nothing went wrong, just return guess
        else:
            return guess


#Define a function called play which takes a parameter called done
def play(done):
    clear()
    #creates a variable called secretWord, which stores a random word from the words list we created at the top
    #Kenneth explains how the random.choice works.
    secretWord = random.choice(words)
    #Create two empty list, we will append to these lists later.
    badGuesses = []
    goodGuesses = []

    #Inifinite loop again
    while True:
        #We call the function draw() with these 3 arguements, on the first iteration of this while loop
        #they will of course be empty, the first 2 lists, so our draw() function just prints "_____" x amount of
        #"_" underscores, to represent that there goes a letter, which you need to guess and the secretWord arguement
        # , just gives the draw() function the value of secretWord, so it can do the comparisions etc. inside our
        #draw() function.

        draw(badGuesses,goodGuesses,secretWord)

        #Here we call our function to request an input from the user, and we give the function 2 arguements (badGuesses,goodGuesses)
        #so that function can do the comparisions as well inside of it :)
        guess = getGuess(badGuesses,goodGuesses)

        #Here's where we actually check if the letter the user guessed, is inside the secretWord that the computer
        #picked from our words list.
        if guess in secretWord:
            #If the letter guessed by the user IS inside the secretWord, append it to the goodGuesses list.
            goodGuesses.append(guess)
            #create a boolean variable called found, this is just a tracking variable
            #It keeps track of "where" we are in the game basically
            #Set that to true, because we have found a letter inside the secretWord
            found = True
            #Iterate over the letters in the secretWord list
            for letter in secretWord:
                #if the letter of this iteration is NOT inside the goodGuesses list set the found variable to False
                #This checks if we have found all the letters inside the secretWord list (ask if you want me to break this down)
                if letter not in goodGuesses:
                    #Set the found variable to False, because we haven't found all the letters inside the secretWord list yet.
                    found = False
            #if found is True:
            #This will get run if we have found all the letters inside of secretWord
            #because of our tracking variable found, was not changed, as the if condition inside the for loop above, was never run on this iteration.
            #The found = true above is still True
            if found:
                print("You win!")
                print("The secret word was {}".format(secretWord))
                #done is another tracking variable
                done = True
        #If the guess is not inside the secretWord list, (the letter the user guessed wasn't in the secretWords lsit)
        #run this else clause
        else:
            #append the "bad" letter to our badGuesses list
            badGuesses.append(guess)
            #If the length of our badGuesses list is equal to 7 (there's a total of 7 letters inside our list)
            #then end the game, which our done tracking variable will do for us. 
            if len(badGuesses) == 7:
                draw(badGuesses,goodGuesses,secretWord)
                print("You lost, the secret word was {}".format(secretWord))
                done = True
        #if done is True;        
        #prompt the user for an input, asking if he wants to play again, again lower capitalizing the letter the user gives.
        #if the input is NOT 'n" (no) meaning yes ( in my opinion it would have been cleaner to just say if playAgain == 'y'
        #but whatever. 
        #then go ahead and return play(done=False) which will call our play() function with the arguement of done, which has a value of False
        #The reason it's set to False is so that we can "reset" the game, we will be given a fresh pair or lists (badGuesses and goodGuesses)
        if done:
            playAgain = input("Play again? Y/N").lower()
            if playAgain != 'n':
                return play(done=False)
            #if the user however said 'n' (no) then just call sys.exit()  which just tells Python just exit. essentially killing the game:)
            else:
                sys.exit()

#Our welcome message to the game
#prompt the user, asking if he wants to exit the game early
#You should know by now what the rest means :)
def welcome():
    start = input("Press enter / return to start or Q to quit").lower()
    if start == 'q':
        print("Bye!")
        sys.exit()
    else:
        return True



print("Welcome to letter guess!")

#This sets the starting value of done to False
done = False

#Here we just call all the functions we need, to begin the game.
while True:

    clear()
    welcome()
    play(done)