Downhill bike suspension

Simple : 2 circle colliders for the wheels , one polygon collider for the bike’s body. I need to get the suspensions to work properly and I don’t know where to start

What you are looking for are probably a spring joint.

You can find the official unity tutorial video for it here: Spring Joint 2D - Unity Official Tutorials - YouTube ,

and the manual for it here: Unity - Manual: Spring Joint 2D