I think it depends on the rabbit.
Inky never worked out how to do ramps until he saw Smokey hopping up and down them. I was shocked because it was the first time she had ever seen a ramp but she was just straight up it!
I would make sure he has food, water and bedding on the level he is on at the moment and really just leave him to it for a few days. Rabbits are quite inquisitive, so I'm sure he'll try and explore a bit more when he feels safe.