To litter train a rabbit, you should start by placing a litter box in the rabbit's cage or living area. Choose a corner that the rabbit naturally gravitates towards for urinating or defecating. Fill the litter box with rabbit-safe litter such as paper-based or wood pellets. Whenever you see the rabbit using the litter box correctly, praise them with a treat or affection. Clean the litter box regularly to maintain hygiene. With patience and consistency, your rabbit should learn to use the litter box for their bathroom needs.