It's a skill issue, I guess, but I can't go further the first "x for grap" mechanic. If I could hold to the wall longer it might help I think. Because if you don't play platformers a lot, this kind of things need some time to master.
It's simple, just keep pressing X While on one side, face the wall, then press Jump again. You will rise slightly, and quickly press X. Pull yourself up against the wall, then repeat the process.
