In your case you want to do something with XML.  XML is a serialization format that is meant to represent some sort of structured information.  A simple example might be a file directory listing, which begins at a "root" position and then consists of a list of "rows" of data.  Each row could have a number of attributes (file size, creation date, name, etc.) and it might in turn have another list of items within it if the item is a directory itself.

When your program receives or reads this XML document, it may need to extract the information from it or search within it.  You can parse the XML text for individual pieces of information, or you can parse the whole thing in one pass, building some sort of object hierarchy.

One common approach is to use a generic XML Document Object Model (DOM) library to hold the parsed information.  There are a number of XML DOM libraries out there, and most of them include parser/serializer logic wthin themselves.

However you seem to be asking about VB.Net in the Classic VB forums for some reason.