Hi Taurog and welcome to the forums!
This tutorial is aimed at the intermediate PS user and as such, assumes that you are familiar with photoshop somewhat. The Keeper specifically notes in the introduction to the intermediate section, that new photoshoppers may have a hard time follwowing these tutorials.
Photo touch up is quite an advanced technique(s) using PS, and one of the more complex things you can attempt as a beginner. I read through the tutorial and I dont see any steps missed out, but rather, the tutorial assumes you know how to do certain things without going into details (making selections suing quick mask etc).
Now dont give in just yet. I personally would slow your self down a tad, and try doing some beginners tutorials to get familiar with some of the fundemental PS commands/techniques and then building upon what you have learnt, move on to some ore advanced tutorials.
I can still try and help if you can be specific at which step in the tutorial you do not understand. I cant explain anything without more details at which step your stuck on!
let us know and happy photoshopping!