Arcanum: Of Steamworks and Magick Discussion

Can somebody explain the crafting system/tech disciplines to me? The manual is not answering the questions I have

I am attempting to craft bullets, I have learned the schematic, but I understand that I need 5 in the explosive discipline in order to craft them. I have 0 in explosives currently and am grinding gold to get a book at Tarant university to level it.

When I level up a discipline, does it go up by 5? and not by 1?
also, outside of books bought at universities, how else can I level up disciplines? is it only through spending my level up points?

The manual doesn't explain this (atleast well enough for me to understand), The only arcanum wiki I can find is pretty shit, and I don't want to make an account on Terra-Arcanum juuust yet

I liked it. I had multiple runs, majority of them ended prematurely (either bug or stuck on my own, that was many, many years ago), but not that many years ago I actually did finish one run with a simple ork fighter. After that I feel no more urge to play it.

I wouldn't mind an Arcanum 2 though.