I've never done it, but these are some thoughts I've had. (I like to watch YouTubes with dogs in them.)

Put a mat or old towel in the tub so the dog's paws aren't slipping all over.

Run the water so slowly that the water all goes down the drain. Don't let the dog see water filling the tub, so he thinks he will eventually drown.

Use a sprayer which is nice and quiet. Use nice, warm water.

Give treats at regular intervals.

Talk cheerfully or sing. Convey that everything is fine.

Let a new dog watch an old dog get a bath and see that the old dog is calm.

Ask the vet if it's really necessary to wash the dog's face. That seems to be the trickiest part.

Think about the amount of hair going down the drain. If you are causing a plumbing problem, how can you avoid it?