How would I make a suspension script like the one in this video?
idk, i guess try this tutorial, ROBLOX Easy Suspension Tutorial Part 1 - YouTube, it has 3 parts and it seems to be what your looking for
As @56ytr56 said, check the Tutorials first, and always use the Search tool up top since this question has been posted so many times…
Sleitnick has a very helpful series on how to rig a car. One of the videos covers constraints and suspension.