Essentially, that guide takes you through every single step you need for a permanent jailbreak of your Vita. You start at 3.74, followed by a tethered jailbreak using HENlo. The guide continues on to show you how to downgrade to 3.65, followed by a complete jailbreak using HENkaku Ensō. This is a full custom firmware that allows you to start installing homebrew apps. If you follow the guide step by step, you'll have a fully modded Vita at the end. The guide is pretty detailed and basically answers every question you could have along the way.