Dj is exploring the world through his mouth. Babies use their hands and mouth, puppies just have their mouth to explore with.
Next time he bites you, yelp in a high pitched voice and walk away. This is mimicking the behaviour his siblings would do and he'll learn that he won't get attention if he bites. You could also teach him to have a soft mouth, so this means he's allowed to gently mouth your hand, but the second he gets rough you yelp and move away.
Every time he is biting something he shouldn't, put a chew toy in his mouth instead. This gets tiresome to do consistently, but he'll catch on. Yorkies are smart little pups
My pup is just under five months, and I still have some things stored out of her reach. I'm slowly moving things back down, but we take it day by day. (I just turned around while typing this and noticed Indy chewing a blanket hanging down from my bed. *sigh*)
Good luck!