When people ask me how to potty train a puppy (I write training articles and teach a puppy training class) I always start by telling them the same thing. Teaching your puppy can be a lot easier than you're expecting but you need to stay consistent and patient because puppies learn by rote and repetition.
It can take anything from a few days to a few months. This is the first thing people want to know when looking at how to potty train a puppy. The deciding factor is both the individual puppy his or herself and the method of training used. Some trainers tell you that you can house break a puppy in only a few hours and I don't think this is true in any case. It can take anything from days to months with maybe 2-4 weeks being the average in my experience.
One of the easiest ways to potty train a puppy is to constantly take them outside (they only have small bladders) and praise them when they pee. If you catch them doing so inside you scold them in a firm voice and move them outside. That's all there is to it.
There are a lot of other techniques from using paper newspapers or even litter trays and expensive products but young puppies learn easily and if you are firm with your training schedule and patient with your puppy thats all you need to work out how to potty train a puppy.