Not All CC Shows Up

Oh I'm sorry, I must have misread, I thought you said you were putting your Sims in the Mods folder.

Some tips for finding CC after it has been installed:

For Lots and Sims, open the Gallery and go to the My Library section. If they do not appear, then look at the menu on the left, find the button that says Advanced and click it. Place a check mark into the box for the two options to include content you don't own and to show custom. Now all of your lots and sims should be visible. (You have to do this every time as the advanced settings won't save!)

For clothing, makeup, hair, etc - Open CAS. If the recolor is not a standalone item, then you will need to find the original and look through every single color swatch until you find the recolor. This can be incredibly tedious and it is a shame that EA didn't try to sort these things better. Some items are specifically for a certain clothing set, such as Formalwear, and unless you sort CAS to show only Formal items, you won't see it.  Or, conversely, unless you turn off all sort options you won't see it.

For objects, walls and floors, you'll find them in build/buy mode when you are creating or editing a house. (If you're lucky, the creator will have an outline or a mark on the items so you can tell which ones are custom.)

If you can't find something - make sure your game is fully patched (You may need to turn off Origin and turn it back on again to force an update). Also, check the notes on the download to make sure that it doesn't require a separate mesh that you need to get from somewhere else, or that it wasn't based on an object for an expansion you don't have, such as Outdoor Retreat or Get To Work.

If you've done all of the above, try downloading the item again. It's possible that the download didn't finish properly for whatever reason, especially if you were downloading multiple files at once.