The fastest way to get to the remote and cold Hebra Region (and its Tower) is from the Rito Village. Simply head northeast along the path, dealing with the many enemy camps scattered along it. The temperature will rapidly decline so be prepared with some warm outfits or warm food.
Hebra Tower is unusually short but there are a lot of ice crystals surrounding it. By far the easiest way to get past the ice crystals is to use Revali's Gale so that you can bypass the crystals. Alternatively you can melt the ice. Use fire weapons, light a weapon on fire, or use a bunch of flint to burn the ice away.