How can you not find that basic information? Even Wikipedia has a good explanation? I mean, seriously. This is basic data structures 102 - there are tons of books about it. There are sites about it. Wikipedia describes ton of methods to do that. How the .NET framework does it is not important (implementation detail) as it may change between versions, and even then - the source code is public, so "no information" is wrong again.
For example here you can find the official source code for a 3.5 version.