You can find more detailed information on using Mods and CC in The Sims 4 here. Script mods can only be read that deep, but if you like you can sort CC a bit deeper at 3-4 layers. You can organize your mods folder by using 1 level of subfolders beneath The Sims 4/Mods/ but no more. See each mod's installation instructions for further info.

Mods that are zipped may need extraction. Mods Must Be Enabled in the game options menu in order to work. Mac: Use Finder and go to /Electronic Arts/The Sims 4/Mods/ Windows PC : /Documents/Electronic Arts/The Sims 4/Mods/ Mods are placed in your hard drive, but it varies between PC/Mac: For this reason I decided to curate a list of good-quality mods that are up-to-date at time of writing, and revisit this at times to remove mods that fall out of date and add new finds.

Many modders have their own sites and do not host their files elsewhere, so mods for this game can be a bit scattered. Mods can add a lot of value to players who are looking for new experiences in The Sims 4, or when they're a bit bored between new Expansion Packs. The Sims 4 Mods Carl's List of The Best Mods for TS4

Sims 4 skins mods