How to install Custom Content and Mods
Step 1: Every mod/custom content should be placed in My Document>Electronic Arts>The Sims 4> Mods
Step 2: If the cc/mod you download is in .package format, you can place it anywhere you want in the Mods folder. If it is a SCRIPT mod, you cannot place it inside a sub-sub folder. If it's a ZIP file, first unzip it and follow the instructions above.
Step 3. Enable cc in-game. If you're using script mods, also enable script mods in-game.
Example of what it should look like inside the mods folder...
Below, you can see how I arranged my mods folder - by date of download. This helps me find my custom content and mods with ease.
Example of what it should look like inside my sub-folder...
Below, you can see that I have both package file and script file together. So, I have the main folder (MODS), then my sub folder (030221-mortem-v080621), then last are both package and script files. I do not keep them deeper than that.
Hope that helps ♥