It's insane to do this kind of work having never done "anything like it" before. I can understand why the ground crew were swearing and cursing at you. It sounds like all were fortunate that no-one got hurt. It would have been very easy for you to have taken off a finger or two, or worse.
The only way you get good at this is practice. I love the fact that these guys are quoting formulae at you to help you. Only on PPRune!