OK, I guess I should dumb the descriptive comments down a little next time, but this script isn't for beginners, so really, I don't have to describe anything more than what is already said in the first post.
If you can't understand what the comments mean, you should really learn about key words in C# before attempting to work with any script.
Here's a little help for newer developers:
C# Keywords (C#)
OK, now for a small implimentation guide for this system...
[RUO X] World of Warcraft Level System Utility/SDK Implimentation Guide