It is best to brush the dog's hair before washing, so that it is not easy to knot after washing
If you have a shower head, use a shower head, if you don't have one, put it in a basin, wet the dog hair thoroughly with warm water, and apply a dog shower gel (I suggest that it is best to use dogs, pet stores should sell it). If you don't have one, use baby shower gel or soap if you have to, instead of shampoo and clear soap). Massage for a while, rinse, dry.
When the dog's hair is not completely dry, do not let the dog go out or let the cold wind blow, so it is easy to catch a cold.
Be careful not to get water in your eyes and ears.