It's actually very easy. Just follow the signs for Transit. Once you get the transit area and you already have your next boarding pass, all you need to do is go through Transit security and you'll be back in the central terminal area. If you don't have the next boarding pass there is a transit desk in the transit area that can take care of that for you so you do not need to go through immigration. Assuming you're luggage is checked through to the final destination that is. Just be prepared to do a lot of walking as its a very long airport.