Even if it's a house rabbit, you'll want to confine the bunny at first until it learns to use a litter box. Use a playpen or cube grids for this. Rabbits tend to go pee in one corner of their cage, so place a litter box there. Use a larger litter box, not a small one. Some people like a litter box with an inner grid to keep pee confined to a pee pad. Use either aspen wood pellets or compressed paper litter pellets in the pan (even if you use a pee pad in the bottom). Be cautious, many litters are dangerous. Yesterday's News or Gentle Touch litters are good. In the beginning you may also want to add some Critter Litter Potty Training litter as the smell makes them want to pee there. You can stop using that after the rabbit is trained. Place the box in the corner where she pees. Add the pee pad if you're using a litter box with a grid, then place the grid on top of that. Add either the aspen or paper pellets. Add a bit of Potty Training Litter. Place your rabbit's hay rack over the litter box, so the hay falls into it as they munch. Your rabbit will like to sit in the box and eat their hay. They may also eat some of their poops, as rabbits are coprophagous and will eat a special kind of poop they make called cecotropes. Your rabbit should start to use the litter box. If they use a different corner add a litter box there as well. They will eventually learn to go in it. Keep them confined to the smaller playpen until they use the litter boxes well. Rabbits that aren't fixed may still spray to mark their territory, so it's best to get them spayed or neutered. An unfixed rabbit can be a bit of a menace.