Help.

I have gone from the lift and up through the mountain.  Communication "Having trouble getting out of there? You are going to have to make a foothold."

Where and how do I do this?

Righ after you come out of the big vertical tunel with all the VS jumping, there is a big rock that either falls down on its own or has to be shot with a rocket, and then you can do the Y jump on the jumper mech to get to it, and another Y jump to get to the boss.