The long coated rabbits need to be combed up to two or three times a week! And some shed! In order to keep up with rabbits with long coats, some breeders use a dog blow dryer with warm forced air that blows away any mats.
Otherwise it is good to brush out a pet by hand.
First sit where your rabbit won't be disturbed by others. You'll need your grooming supplies such as brushes and nail clippers. Put your bunny on your lap and calm him down. Then use a pin brush over the coat. Part the coat and brush from the inner part of the coat out. Use a wide tooth comb. Then a bristle brush such as a boars hair brush. Clean the ears and then cut nails.
If you must, you can find a groomer such as a breeder who grooms rabbits or such. You can also trim the hair with scissors holding it away from the body so you won't cut the skin. This is very important to not cut the skin. Make sure to gently brush out the mats or blow them out with a cool hair dryer.
