How to Install Custom Content on a Windows ComputerTo start installing custom content, you'll need to download some files. Custom content files are saved as .package. Some CC comes already ready to go in this form, while others need to be extracted from .zip or .rar files. You can use WinRAR to open these files.
Next, make your way to The Sims 4 folder in My Documents. On most versions of Windows, there should be a shortcut link directly to My Documents on your desktop. Click on Electronic Arts, then The Sims 4. In that folder, you'll find another folder called Mods. This folder will be the home of all of the CC and mods that you download. Simply copy and paste the files that you want to install into this folder. If you want, you can organize it by category. In my folder, I have subfolders for clothes, hair, objects, walls and floors.
There is one last step before your CC will show up in the game. Open up your game, and go to the Game Options in the menu and select Other. Check the box next to Enable Custom Content and Mods. You'll also want to check Enable Script Mods if you want to run any mods that affect gameplay. Save your settings, restart your game and you should be good to go.
Note: After each patch update, you'll need to re-enable custom content in your game in order for it show up again.