Hi and welcome to YT
. So glad you found us!
As you probably know, this puppy should still be with its Momma until at least 12 weeks old -- some very important stuff goes on during that development time that your pup will now miss out on. Also, his young age makes him VERY vulnerable - so please keep a very, very close eye on him and if anything in the least goes wrong - get to a vet ASAP.
As far as feeding, this pup needs a mid day feeding at this age. He should be eating about 4x a day right now, then down to 3x a day around 16 weeks or so.
For training, follow this link to the Training section and see the Sticky Threads that cover potty training here:
General Training Questions - YorkieTalk.com Forums - Yorkshire Terrier Community