You clip a dogs nails by using nail trimmers made especially for dogs. You take his paw into your hand and clip on nail at a time, carefully, only cutting back about a quarter of the nail each time being careful not to cut into the quick. Dogs with white nails are much easier to clip than those with black nails because you can see the blood in the white nailed dogs. You don’t want to cut back that far or you could cause your dog to bleed and it’s painful. Some vets and groomers are kind enough to show you how to do it, so it might be wise to do a little asking.