To get to the Greybeards, you must first go to a place called Ivarstead. There I think you need to cross thre bridge or something to get to the thousand steps (and there literally are a thousand of them). Don't try to get there by just climbing the mountain on some random spot, it's difficult and you'll almost definitely fall and die :D Just climb the steps, follow the road. There are some obstacles on the way, like the snow troll, but I tend to just try to sneak past it because if I haven't levelled up enough, it kills me. There might be some other things on the steps, but those are easy to beat I think.
Does that help? If not, just say so and I'll try again :D Also, if you give me your email, I could email you and I can help with any problems you might have. I'm no expert but I have spent way too many hours on the game, so... :D
Author's response
Oooh! I'll try that. I'll put my email on here in a second, but it's penina.d@hotmail.com :D xx