Hello gayancc,
The simplist case is taking some text and colorizing it. There is a code sample on the home page of the project, but here it is:
string colorizedSourceCode = new CodeColorizer().Colorize(yourSourceCode, Languages.CSharp);
If you want to do something else, like add support for a new language or change how the text is colorized, for instance, please let me know and I can provide a sample.
I hope this helps!
Cheers, Drew