A Mac User's Best Friend!/PLEASE READ BEFORE POSTING ANY NEW PROBLEM THREADS!!!!!!

Can anybody help me??? I've recently got a new MacBook Air (13-inch, 2017) with MacOS High Sierra, I've downloaded the sims 3(as its one of favourites) but it won't work, I've seen a lot of this problem looking through forums and watching peoples videos etc. but I've never fully understood how to get it to work or even if it does work anymore, if anybody could explain how to get it to work that would be great, thanks!