Moving Treehouse projects to Git repositories.

I have made it through the 'merging' section of the Git Hub tutorial. I am at the place where I should have everything I need to start using Git to keep track of changes to my work. The only problem is that I am having trouble tying what I've learned together. I figured that a good place to start would be to commit the files of one of the Treehouse projects that I have already worked on. I created a new repository with the name and location that I want. I go into the repository in my terminal and that is where I get confused. Should I use the "git add" command and somehow add each file individually? That doesn't seem right to me because I am not in the folder with the files that I want to add. Can I directly change a working directory to a git repository? I will continue to investigate this on my own, but I thought I would post the question in case nothing turns up. Thanks a lot in advance.