All aspects of IMF are taught to you by an instructor. If you don't want it to be painful I suggest being a fast learner.Do they teach you how to do your climbs when you get there or are you expected to know when you arrive. Might sound like a stupid question. Also how many sit ups and crunches are done during the abs circuit
Ropes are initially taught on short ropes in the upstairs gym because there is a knack to the technique which takes practice and some get it faster than others. It's all in the legs - but if you have good core strength that helps you do bigger shifts and be able to climb more quickly.
Abs are typically 3 sets of 20-30 reps IIRC, but they vary it depending on how knackered the class is and how often the retards **** up doing it properly.