To this day, I find the APIs for most XML parsers to be quite confusing. Typically, you can breeze through the documentation of an API and get a pretty good idea of the different classes or functions. XML parsers are supposed to provide a Document Model (DOM) and/or Simple API for XML (SAX) interface for programmers to use, but too often I look at the APIs and it's hard to figure out where to start.
You've probably guessed where I'm going with this... Sun has a nice tutorial for using its Java XML Parser (JAXP). It takes you step by step through using JAXP for DOM and SAX parsing. Give it a try.