This link on grooming from the Yorkshire Terrier Club of America may help a new owner, but of course assumes the dog is calm and not frightened. I might mention there is a vest a dog can wear and seems to work for dogs frightened of storms.
As the previous poster mentioned, it is dangerous enough to groom with a calm dog, no less one that is moving to get out of the situation. I would advise caution at all times.
The Yorkshire Terrier Grooming Tips- America