As usual, in Black & White you battle through eight gyms before taking on the Elite Four, with a few notable differences. We also note the significant trainer battles below.
The first gym features three leaders, each specialising in a different type of Grass, Fire or Water. You only fight one of them, depending on which Pokemon you chose as your starter. In the final gym, you fight one of two trainers depending on which version you have. However, their Pokemon are exactly the same.
When you reach the Elite Four, you can now fight them in any order you wish. The first time you only get to fight the Elite Four, then there is a diversion into some more of the game plot. Later on, you can rematch the Elite Four and take on the Champion.