Taken from that thread:
How to Install Tale of Kingdoms?
Install the latest version of ModLoader
Download Tale of Kingdoms
IF YOU ARE UPGRADING FROM A PAST VERSION, DELETE THE OLD KingdomMod.props FILE OR YOUR GAME WILL CRASH. ALSO BACKUP YOUR WORLD SAVE AND KingdomModSave.dat BEFORE UPGRADING.
Move the entire ZIP Folder into your ".minecraft\mods" folder.
Start the game!