Quick PT question

[Baintz]

Have decided to finally get PokertTracker as am now playing more than just casually.
However, I'm an idiot when it comes to understanding anything technically minded to do with PCs, so was just wondering if there is a sticky somewhere that walks you through downloading and setting up PokerTracker and PokerAce, or is it all pretty self explanatory on the site?
I just had a look at the site and was unsure what I needed to be clicking on. It says there is a new patch to deal with the Party upgrade. What the hell is a patch? Do I need it after downloading PT, or do I just want that on its own?

Any help for a clueless technophobe appreciated.