HI and welcome to YT!
Getting this new dog is not only stressful for you, but for HIM aswell, please take this into consideration when it comes to the way you will be handling training this dog from here on
I have had big dogs all my life too and now that I have a yorkie, I do believe different dogs respond to different training methods (though I would never hit a dog, big or small). My advice to you would be to treat this as if you just got a new tiny yorkie puppy.
1. Yorkies are notorious for being difficult to potty train, if the previous owner lapsed on this, it is now up to you. Do not enter into this training with frustration or anger, as this will not accomplish anything but confusion and even fear in your dog. I trained Ziggy to be able to use pee pads and go outside. Firstly I took him to his potty area every hour or so and waited no longer than 5 minutes for him to do his business. If he did it I would give LOTS of praise and say "Good Potty" (yes I named the action, now I can tell him to pee on command
) if he didn't, we would go back inside and try an hour later. This continues and eventually your dog will learn that there is a specific place they should pee. When you catch him in the act of peeing where he is not supposed to use a stern NO POTTY!, and take him where he is allowed to pee. If you do NOT catch him in the act and find "evidence" DO NOT rub his face in it as he will not understand what he did wrong. Just clean it up and try again. This will take patience and understanding if you are to succeed, but it can be done.
2. Yorkies are notorious for also being fussy eaters. How much does your dog weigh? Depending on his size, he might not eat alot/ You could follow the weight/size of food guideline on the side of the pack of food, and your vet would definately be able to assist you on this. I believe your yorkie should be eating quality DOG food. To help him adjust to eating on his own, I have read on here about time restrictions. You could break up his daily meal into 2-4 servings (depending on his size) You place the food down in his eating area, give him 15 minutes to eat, then remove it at the end of that time. Eventually they learn to eat in that time. I personally FREE feed Ziggy because of his tiny size, but I do watch him and make sure he eats periodicly.
Above everything else I would really hope that you BOND with this dog, if you show him love and attention he is more likely to WANT to please you.. There is one last thing yorkies are notorious for, and that is UNCONDITIONAL love. See him as an individual and find training techniques that work for him, love him and he will reward you with positive behaviour and ofcourse great yorkie kisses!
Good lick and I hope some other member have more suggestings for you that might help