Before you even bring you dog or puppy home decide where exactly you would like them to go potty outside. Make sure everybody in the family knows where the area is.
As soon as you bring the dog or puppy into your home give them a drink of water. When they have finished take them outside to the designated area and wait for them to go potty. As soon as they have done their business make sure to make a big fuss over them telling them "good dog for going potty" or something like this.
You should always have a feeding routine for your dog or puppy as this way you can keep track of when they will need to go potty. It is a good idea to take water away from them say around 7 in the evening so that they will go potty before you go to bed and and will not go again during the night.
A dog or puppy will usually need to go to the toilet soon after eating, drinking, after a nap and first thing in the morning. If you wake up to a mess do not scold your dog or puppy as they will not know what you are cross about as they live in the moment and forget what happen a fews hours or minutes ago.
If the dog or puppy does not go when you take them outside bring them back in and try again after 10 minutes or so. Whatever you do do not scold or be angry with your dog or puppy as they are just learning and mistakes can happen.
If your dog or puppy does have an accident it can be cleaned up. If it is on a tile or wooden floor you can clean with disinfectant but if it is on carpet it needs more attention as using some products can actually encourage a dog to go there as they can contain amonia which is also in urine. The best thing for cleaning carpet is probably white vinegar and water.
As the dog or puppy gets older they will learn to give you a signal that they need to go outside. Some will bark others will run back and forth while others may scratch or bang at the door. It is important that you notice the signals and do not ignore the dog as they may end up just going on the floor.
The most important thing to remember when house training a dog or puppy is that you have to be patient and persistant.