Problem

The Downloads I installed can’t be found anywhere in my game

Solution

This can have several reasons

Follow instructions here: Install Sims3Packs
Make sure you did not just download but also install them.
Make sure the files have not uninstalled themselves again.
If a creator has used package files in their creation, you won’t get those automatically. Because of this, the Sim or house you’ve downloaded from the Exchange can look different in your game.

Follow instructions here: Install Package files
Subfolders are only recognized if your resource file is set up to support them.
Make sure that the names of the folders match the instructions given
Maybe you have downloaded something bad. Use the 50/50 method or Delphy’s Dashboard.
Delete your Cache Files
Try something easy like a pattern or a piece of clothing to see if nothing is in your game.
Facial hair can often be found in make-up, especially if they’re older.