Have you tried getting the puppy sucking on your finger and then while it is sucking, move it onto the dogs nipple? You have to hold the nipple for him and gently squeeze a few drops of milk into his mouth. Try that and let me know what happens.
Now you have two options.
1. Take him to the vet where they will tube feed him and hopefull teach you how to do that.
2. Go to the pet store and purchase a feeding bottle and puppy milk replacer (kmr or esbilac brands). But if he does not feed off the bottle, you are going to have to take him to the vet for tube feeding anyway.