For a visual walkthrough on how to properly set up mods and Content Manager, check out this guide:
If the car model is black or invisible in-game, ensure you have the latest version of installed via Settings > Assetto Corsa > Custom Shader Patch .
Search for "Seat" or "131" to ensure the car appears in your roster.
A green "hamburger" icon (three lines) in the top right corner will start flashing or turn green. Click it.
Navigate to your Assetto Corsa installation folder (usually: C:\SteamLibrary\steamapps\common\assettocorsa\content\cars ).