So cool that you can have a space dedicated to your pets!! I would recommend having a hidden house, litter box (multiple if you have more than one bunny), of coarse a bunch of toys to keep them occupied, maybe a basket (with uncured wood) with hay in it as a snack bar, tunnels, and cardboard boxes. Its always good to have plenty of toys that you can switch out so your bunny doesnt get bored. Don’t forget to bunny proof the room so any exposed wires should be covered. any spaces that the bunny likes to dig or pull at the carpet you could put a Timothy hay mat in place of it. My bunny is free roam in my room but I have an X pen setup for her with her litter box and food just in case I have little cousins around or when I am going to be gone for a few days and someone needs to take care of her. To help them feel more comfortable you can take something of theres from there previous set up and put it in the new room. Good luck on your new space!!!