What you’re going through is pretty normal although you seem a bit extra anxious. As you do it more and more it will become easier. It’s fine to not know how to do things, if you ask people they will try to point you in the right direction.

One thing I find is to just accept that sometimes you’ll fuckup but the nice thing is that the only person it affects is you. If I book an appointment and I don’t bring the right documents or I miss it, that’s OK I can wait a few weeks and do it again no big deal.