I think the best route to go would be to call the breeder of your cat and have them teach you. I'm sure they will be happy you are showing him/her and will be glad to show you the proper way to groom - especially since you are representing them by showing one of their cats. From what I understand, Ragdolls are not terribly difficult to groom for show. I have heard their coat does not mat, but I am not an expert as I show shorthairs!
If for whatever reason you are not in contact with your cat's breeder, you may want to join this yahoo group - it's for Ragdoll owners and I am sure they can give you grooming tips. You will need to register, but it is free.http://groups.yahoo.com/group/Ragdollpet/
Are you showing in TICA?