In Pokemon Platinum how do you go to the Pokemon league?

[First of all make sure you have a in your party Pokemon that know the HMS surf, waterfall, rock smash, and strength] After you beat the 8th gym leader [volkner] go to the beach and use surf [ if you don't want to fight the wild Pokemon I suggest using a repel] Keep going straight through the water until you get to a waterfall, use waterfall go to the land on top [if needed heal your Pokemon in the center to your left] enter the cave [this cave is victory road] and proceed through using the HMS I mentioned in the beginning [again i recommend using a repel since the wild Pokemon are strong here, also bring your best Pokemon because there are strong trainers here] after you finish the cave go up to the little lake use surf to get in then us waterfall to get to the top hop on the ground and enter the Pokemon league recommend catching a gyardos because it can learn surf, waterfall, rock smash, and strength]