You need to download the game and it's expansions.
You need to update your game to our current game patch. Wowwiki 3.3.5a patches
You need to create a game account! Click here
to register for a game account.
You need to change your realmlist to connect to our servers.
Inside your WoW Folder, Click on your Data folder
Then the next folder you should click on can be one of the following (enUS, enGB, frFR, esES).
Now look for a file with the name realmlist.wtf and open it with a editor program like notepad.
Replace all the text inside the file with the following line: (Save the file and close)
Wotlk -> set realmlist forums.deathknell.cc
Cata -> set realmlist forums.deathknell.cc:3725
Tbc -> set realmlist logon.deathknell.cc:3726
Now open your game by clicking on wow.exe
DO NOT ATTEMPT TO CLICK ON launcher.exe!