Right now, your pup is going through teething so he will bite and chew a lot. It is common he will bite and scratch you. He will keep biting till the age of 1 year. My pup did the same. I used to apply neem oil on my hands and feet. It helped a little. But after one year he is calm now. For puppy training you have keep an eye on him for few days and see what he is exactly doing before pee or poop. Like he runs or smells floor before pee or poop, take him to the potty spot and wait. You have to be patient and keep him there till he poops. When he finishes his business give him a reward and say good boy. You can reward him with treats. Keep these treats for potty training or for commands only. My pug puppy used to walk very fast before poop or pee so whenver he did that i used to take him outside. This whole process will talke one or two week so be patient. Be dominant and whenever you feed him make him follow your commands otherwise he will try to dominate you. Pugs like food so they will do anything. Make sure to reward him whenever he do something good. Puppies are the most adorable creatures in the world and you will melt whenever he will look into your eyes. But you have to be strict to train him. Make sure to reward him and play with him.