once you've pad trained your puppy, you can move your potty pad around the house and your puppy should know it's the right spot to potty. i have bunjee's potty pad in the kitchen and if he needs to go at night, he'll get up and outta bed, walk to the kitchen, pee, and come back to bed. if i left a potty pad in the hallway (which he'll see before he goes into the kitchen) then he'll go to the first potty pad he sees.
he doesn't like to go outside unless he really really needs to. and he actually won't go on command unless it's on a potty pad or something similiar. so when we're out, i'll carry a small potty pad and tell him to go on the potty pad. if i'm desperate, i'll go to a public restroom, lay down some paper towels and tell him to go and he will if he needs to.
as for going on command. in the beginning i'd bring him to the potty pad every 30 mins or so and tell him to "go potty". when he goes, i continue to tell him "go potty" while he's going and when he's done, i tell him "good potty", lots of praise and a treat. if he goes on the potty pad without my giving him the command, i still reinforce the command and tell him "go potty" while he's going and "good potty" when he's done. i distinguish the command for peeing and pooing. i tell him "go potty" for pee and "go poo-poo" for poo. he's got the "go potty" down pretty well. sometimes he'll pee instead of poo for the "go poo-poo" command, but we're still working on it.
it took us a few months to get to where we are today, so it's not going to happen overnight, but it will, just be patient and be consistent!
good luck!