If you're (fairly) new in TG2, you better stay clear of the blue nodes, and get the hang of the program's 'normal' nodes first. That would help you enormously integrating blue nodes later. A little knowledge of maths is very helpful, although for instance the blue node 'multiply color' and the merge shader set to multiply (color) and level 1 are approximately the same, and are easy to understand.
If you have time on your hand, it's nice experimenting with blues though. Find some clipfiles or descriptions of blue nodes on the forum and explore how they work, change them from there until you understand and have what you need (or might perhaps need some day). That's how I proceeded.