enter the Pokemon league
He first goes to Route 5, close to the place where you two both first met Alder. He then goes to one of the topmost caves at Victory Road, where he can be fought against.
The elite four, the champion, (Cheren, Bianca,you have to find them)and,(Cynthia,after you beat the game)
When you go to Twist Mountain and have to battle Cheren, Alder will give it to you soon after you beat Cheren.
Your Rival will give it to you after you beat him at the end of Victory Road.
Once you beat the flying type gym leader Skyla, head towards celestial tower but don't go to it about halfway turn right and head towards Twist Mountain, there you will battle Cheren, then Alder jumps down and gives you both the HM surf
Cheren is a guy
Victory road
When you get to the end of the victory road in pokemon white or black, you will fight with cheren, your main rival. He will be quite strong (he will have his main pokemon at level 65 and all others at 63). To beat him, just use type advantages or use pokemon higher than 63 in level.
Cheren will be at the end of victory road.
After you beat the game, you must go to route 5 and talk to Cheren. He'll then be waiting for you at victory road.
He first goes to Route 5, close to the place where you two both first met Alder. He then goes to one of the topmost caves at Victory Road, where he can be fought against.
The elite four, the champion, (Cheren, Bianca,you have to find them)and,(Cynthia,after you beat the game)
Alder gives it to you when you beat Cheren at Twist Mountain.
When you go to Twist Mountain and have to battle Cheren, Alder will give it to you soon after you beat Cheren.
using super effective Pokemon against his' Pokemon you'll need a super effective Pokemon against his starter but you don't need to win with super effective Pokemon just stock up on potions that's what I do.
Cheren is in the last room of Victory Road before going to Victory Road. (Meet him on Route 5 first.) Bianca is in Professor Juniper's Lab. (I think after beating Alder, I'm not sure)
Once you have the Dark Stone, go to Opelucid City and beat Drayden. He tells you to go to Victory Road where you'll battle Cheren for the last time before the game is over. You have to beat the Elite Four but won't battle Alder because N appears to have beat him. He says he won fair and square and raises Team Plasma's castle around the Pokemon League. Zekrom will be inside.