CONGRATS, there are few bigger joys in life than having a dog as companion.
Vet would say not to bring him outside until he gets all his shots to not get sickness from dogs that don't have updated shots. Ask your vet. If you keep him indoor, bring dogs that have updated shots to him so he can socialize. First few weeks are critical.
For house training, it works best if the whole family is patient. Small dogs, especially puppies have small bladder. They will want to pee like 15-30 minutes after drinking. I would spot mine drinking then go do an intensive play session and literally put him on the pee mat after. If he doesn't pee on the mat, it's fine, just clean up (use the odor removal spray) and ignore him. If he does, shower a tons of praise upon him when he goes. Do the same thing if he goes outside the house too. He'll make the connection: pee on mat = affection from the humans.
I wouldn't confine him against his will. Treat the cage as a safe sanctuary that he can go in and relax. Put old piece of clothing inside, they like that.
Products I use with great effectiveness:
Disposable pee mat
Odor removal spray, this smells very pleasant and actually remove the odor instead of masking it
First few months will be a bit frustrating but most dogs is fully housetrained and can heed basic commands in 3-4 months.