Do you really need documentation? ...things are pretty sel explanatory.
Just type: "tweakui" into the Start/Run prompt and hit Enter, then expand
the "logon" section and click on "Autologon", check the checkbox and enter
the correct credentials. If the system is not a part of a domain don't
enter anything in the domain field or enter the comptuer's name (either one
should work). If the account you chose to automatically login has a
password, click on "set password", type it in and confirm. VOILA!