Google.
Wonderful site.
You type a question, it gives you answers.
For example, I tried "use XML with datatable c#" and the top site was titled "Loading a DataSet from XML" on MSDN! A quick look, and it tells you how to load a DataTable from an XML file! Try it - it's not difficult, all you have to do is type "www.google.com" in the address bar of your browser, and off you go. :doh:
Looking at this web page gives descriptions, instructions, and even code! Admittedly, it's in VB, but it's not exactly difficult to understand...
Look
here[
^].