Make character interact with object without using unity Physics

I have a task on making a character controller that can interact with the scene, move over slopes, collide with obstacles, fall from high place, but I can not use rigidbody or Unity`s Physics class, I can only use Colliders. I have been searching and trying but couldnt manage to make it work, only way I can think is using collider.bounds but it is so challenging, and I am not even sure what to do.

If you have any idea on how to custom make such character controller, I would really appreciate it. Thanks in advance