can you explain how to install a sim to my game
It depends if the sim is in s3pack format or .sim file.
If it’s in s3pack, then you just click it and wait for your launcher to install the sim. When it comes to .sim files, you have to go to your Electronic Arts folder then > The Sims 3 > SavedSims and drop it there, that’s all! Installing CC is more of a process, you can look for a tutorial about that, there’s lots (✿´‿`)