Hi there!
Here’s what I do! Maybe it gives you some ideas
I use treats (like a cube of carrot) or pellets to get my bunnies in their cage. I see a lot of people use craisins for treats but that’s more difficult to get here in Belgium. And if you’re going to train on something for a while, I think it’s best to use pellets. So you can train him a bit so he understands that going into the cage means he gets something yummy and that it’s not a punishment.
I use a specific hand gesture that signals them to go in their cage and you can use a command with that. I swoop my hand inside the cage with my index finger stretched. My command is “hop!”.
Lure him inside with a treat – give treat/pellet after he jumps in cage – let him come back out – lure him inside with treat – give treat/pellet after he jumps in cage – Start using command and lure with treat – give treat/pellet after he jumps in cage….
Repeat as much as you need to. If you notice it’s going too quickly just back down a step and perhaps add an extra pellet when he stands in front of the cage
How can you see it’s working? The bunny jumps inside the cage without any indication from you, expecting a treat, lol
Hope this helps! Good luck!