I actually wouldn't suggest you to use training pads, as it actually delays the dog's house-training. We tried training pads with Diego for a few nights, sometimes he peed on the right spot, sometimes he didn't, but we never knew for sure if he had really FINISHED peeing.
Later we used a different method: put him in a laundry basket right beside our bed. He was too small to climb out of the basket, so when he tried to, he'd make some noise and that'd wake us up, and we'd immediately get up and take him out, and praise him like crazy when he did pee/poop, and put him back to the basket to sleep. Now that he's older and can easily climb out of the basket, we now put him in a crate at night, and the same routine goes. The crate is placed right beside our bed, so even though he's in a crate, he won't feel lonely. This has worked out great!
Diego can now hold up to 5 hours! The general rule for holding is age+1, so if your dog is 3 months old, he/she can hold up to 4 hours, but this is only a general rule, it varies from dog to dog. Unless you catch your dog peeing IN ACTION, do not yell at him or beat him, it's nothing but cruelty! Use positive reinforcement: a lot of praise, using a high pitched happy voice (like the one you say for "ice cream"), rub his back (not the head, it's considered aggression in dog world), and tell him "good pee good pee". If you catch him peeing in action, tell him "bad pee bad pee", and immediately take him out, and again praise if he does pee. If you can't catch him in action, stay calm, don't make a fuss, just clean up the mess and move on. Make sure you use a deoderizer to completely clean the smell of dog urine, so that he won't smell his own urine and thinks it's OK to pee here. Javex bleach worked best for us, Spot Shot also worked OK, but a little bit expensive.
It only took us about a week to get Diego house-broken, and the rest is more reinforcing the rule. He occasionally still has accidents, but that's pretty much our fault for not watching him closely. You should try to tell a dog's "I've got to pee" face. If he starts to snoop around in circles, he's usually looking for a place to pee, so take him out immediately. When the puppy is very young, they need to go potty right after each meal, and right after each activity: like after sleeping, after playing and after eating, so watch him like a hawk!
The beginning was very hard, and tiring. We couldn't get a full night sleep for about a month, some nights we had to get up 7-8 times, it was very tough, but it was all worth it. Even today, Diego has to get up once during the night, but mostly around 4-5 a.m., so it's not too bad. Believe me if you keep doing all the right things, IT WILL GET BETTER.
Good luck!