Have you made sure that you add all your CC files to the downloads folder? They have to go there in order to be routed into the game. Once they are added to your downloads folder, they will show up in the Sims 3 launcher window under the Downloads Tab the next time you launch your game. From there, you have to select all the content that's listed and select Install.
@Sarah-Downing02 , it can be buggy at times. CC content such as hair, sims, and clothing, works well for me. For installing worlds and other content, that's where I've had some bugs and will generally have to do one install at a time. You can manually delete the items that were added in successfully from the downloads file folder, and maybe for the content that did not go through, try adding in one at a time. It might be that some files are bigger, and since the system can lag, perhaps trying one at a time might work.
