Finally, target experience with an ID selector. Add a background-color property and set the value to lightsteelblue.

For future reference, in order to really help answer your question the community needs to see your code and/or know what lesson/challenge is being referenced. Here's a helpful link to a video about posting a snapshot of your code!

That being said, I think I still understand your question. When we're dealing with CSS we have to connect it to the HTML document in two different ways. The first is by linking the stylesheet in the head of the HTML document. This lets the two documents know that they will be communicating with each other. It's the equivalent of telling your HTML code "Hey code, you need to be aware of this stylesheet because it's going to try to interact with you." The second way, that pertains to this question, is to tell the CSS document exactly which parts of the HTML document it should be interacting with. The way that we do this is with selectors.

There are many existing selectors but the one that we need to focus on is the #id {} selector. An id in HTML is added to a tag to give one specific element or section a unique identification. An id can only be used once in one place, which is what makes it different from a class in HTML which multiple different elements and sections can share. Because we're targeting an id, we're going to use an id selector to let our CSS code know exactly which HTML element it should be styling, in this case it's whatever HTML element has the tag containing the id of 'experience'. Using the above information, we can begin writing the code in question like so:

#experience {}

Now that we've told the CSS to target the element with the id of 'experience' we can write different properties which will change how the 'experience' section looks. Following CSS syntax these properties are going to go in the curly brackets after the selector. The question tells us to use the background-color property in our selector. This will change the appearance of the 'experience' section by changing the color of the background. After adding in this property our code looks like this:

#experience {
  background-color: 
}

We have just one final step and that is to let the 'experience' section know which color the background should be! This is again provided in the question: 'lightsteelblue'. If we add this color (and the semi-colon after which separates multiple property declarations and is part of the syntax of CSS) we'll get this for our final answer:

#experience {
  background-color: lightsteelblue;
}

Hope this helps!