'Let's play Heroes 5 online.'

Hello everyone! I've been playing Heroes for quite some time, and now I want to play Heroes 5 online. I browsed the forum, but I didn't really understand how to do it. I have "Tribes of the East" version 3.0 installed, and I'm using Windows XP. I understand that I need to install patch 3.1, but is it necessary? The game was downloaded from a torrent, so I don't have any keys, which means I probably need to use Hamachi, but I don't understand how to do that. So, my question is: what do I need to play through Hamachi? If possible, write a mini-guide, or point me to one if it already exists.

Sincerely, Moon Fury.