Translation:Please climb up that mountain.
上(のぼ)り gets used for going up stairs and ramps, say. My Japanese teachers recommend you use 下(くだ)り for the opposite though 下(お)りる might do for while you're on your way. 登(のぼ)り gets used for getting up hills, mountains, trees, etc. The opposite is 下りる for going down while still on it or 降(お)りる for getting down and right off of it.