What now?

[Storm]

Okay... I just went with Buck to that stone and he got it and walked away. Where should I go next? I also didnt find a legendary pokemon that is supposed to be in that mountain.

Also.. How do I get in the Snowpoint Temple?

And, at the end of the Victory Road Cave, there is a fat guy standing in front of a cave entrance not letting me pass.. Don't tell me what's in there, but do tell me when I can go in

[Sceptile_Master]

You go back to the town outside stark mountain. Can't remember exactly what it's called but then you go into Bucks house and talk to him and he'll leave his house. then return to the volcano and catch heatran if you wish.

And about snowpoint temple. I think he let's you in after you have the national dex... couldn't be too sure though, all I know is the first time I tried entering I didn't have the national dex and wasn't allowed in and the second time I tried I had it and they let me in. Snowpoint temple isn't too useful though unless you have regice, registeel and regirock.