These dogs are non-shedding, so groom twice a month using tearless shampoo, conditioner, a long, fine tooth comb. Trim his ears, his bottom, and "carefully" remove tear stains around eyes.
The firs thing you should consider doing is making sure you have all the proper equipment you may need. The second step would be to place your yorkie on a comfortable spot on the floor or on a grooming table. Spray your dog with a coat conditioner and water mix. Pin brush.
Be sure to comb him several times a week, preferably daily if you can. Bathe him about once every two weeks or more often if he gets really dirty. Don't bathe him more than once a week or he'll loose the oils in his coat.