@tomas I think it's one of those things that's best learnt by just doing it, and googling individual questions you have.
Obviously you'll need to install it [latex-project.org] and make sure latexmk is included (else you'll have to set it up manually, but it's worth it — live preview, and saves you running pdftex/xelatex and bibtex 4 times to get cross-referencing done).
ShareLaTeX [sharelatex.com] is my normal reference for the more well-known packages. CTAN [ctan.org] has documentation on just about every package around (and there are a lot).
And of course I can send you my default academic preamble if that'll help.