Oh. It's not that difficult. First you need to enter the northern entrance of Mt. Coronet (the entrance between Celestic Town and Eterna City. You will need pokemon with strength and rock smash (Defog can be used, it helps a lot,but you CAN go without it)
Once your in, all the way to the right there should be a narrow passageway going north blocked by a bunch of boulders you move using strength. go up there, and you will enter a foggy room. Use Defog here, then keep following the path north, smashing and moving boulders along the way. After a while, you will get out and find yourself in a snowy path. Follow the path, and you will eventually come to a Blizzard. This might slow you down a bit, and the snow can suck you in, making you move more slowly. Then you will come to the Acuity Lakefront. Head east and you will soon come to snopoint city. Hope I helped!