When Grooming them first you need to have things For grooming like: Brush(Not sharp), Water and Towels.
First to do is to get the Brush and use it From Head to bottom Because if you start in the bottom and end in the head the fur may be Cut many times, You can use hand too when using a hand you just need to pet them then the dead fur may fly away. When Using Water you use hand too Because you Put water to Your hands and pet them so the other dirts will be cleaned too. Towels is for the eyes you need to cover the rabbits eyes so they will not be so scared and towels can use it in your Lap too so the fur that is coming to your Lap Will Be in the towel.
When Grooming them Make sure that you are So patient so they will not be so scared. Scaring rabbit can hurt them selves because rabbits will jump and kick many times. Patience is a virtue.
Make sure you clean the butt, Under ears, Ears, nose and eyes check some mites and go to the veterinarian so check there teeth.
Make sure that the rabbits Teeth is not Getting so long because it cxan Cause a shorter life-span. Causing the rabbits not to eat and Getting to be dead.
When Grooming Find some brush in the Pet stores so you can have a good quality make sure that brush and other items is not sharp. Sharpness for rabbits is dangerous it is not the worst but it can be dangerous.