If you are unsure of claw clipping for your dog, get your professional to do the work for you. Your vet, vet nurse, vet tech or groomer will happily do this work and not get it wrong!
Clipping your dogs' claws can be nerve wracking at the best of times, they move suddenly, you aren't holding the clippers the right way, you don't know where to cut to and it can end in a mess of blood and pain for your dog.
From when you get your dog as a puppy start touching around the paw and claw area and make it really positive and fun. The more you do this, the more they will relax when it does come time to having them clipped.
Ask your vet to show you how to clip them, but if you feel unsure just get them to do it, they do many a day!