My dog and my child... i need help?

The child is 3 years old and understands when you tell d/n touch the dog..I have grandchildren and when they were babies they knew by me telling them to leave my dogs alone when they are sleeping.If they want to play they will let you know..The sooner you teach him the better,just like learning not to touch the stove as it's HOT..Kids know at that age what your saying..