When my bun was young I potty trained him in a few days. You basically don’t have to do much as they are smart and will know where their toilet is once you show them. My bunny is free roam so when he peed somewhere on the floor I just wiped it off and placed the wet toilet paper in his toilet pen on top of his hay. I line the pen with old paper and put a lot of hay on top as bunnies like to eat when they poo. He learned quickly and never did outside his toilet again (except my bed but this was because he wasn’t neutered)
Hope this helped, good luck

They are pretty easily litter trained. You can place the litter box in a corner and you will know whether or not that is working for them. If poops and pee are left in another area, listen to what bun wants and move the box there. I use Yesterday’s News litter, it comes in compressed pellets and is super duper easy for cleanup. I would suggest using that litter and getting a litter screen, then just pile hay in one side and they should get the hang of it pretty easily. I suggest a litter screen because my bun has a habit of digging through her hay and after a little bit of digging she has stomped it into pee soaked litter, and who would want to eat that? Also, a personal suggestion is to make sure that you have a decent sized litter box. The ones sold at the pet store for rabbits are often quite small. I have cat litter trays for both of my buns, and I’m sure they appreciate the roominess

I didn’t use treats; immediate intervention (bring to litter box or coax to litter box) is most effective. I adamantly stared at Wick’s bottom whenever I had time and would intervene. After a bit, I could recognize his usual mini-routine prior to peeing. Pooping is much more difficult because it just happens. I recommend finding a sound or simply “No” so you can say it immediately when an outside-litter-box pee/poo happen and you’re not in immediate distance to re-locate her. Always praise and pet (if your rabbit likes that) when they successfully poop/pee in the box, and even when you plant them in there, do a small pet as well so they end up liking the box.

You can also start at baby steps, which is starting with a small area and widening it as you go.