A little help with tutorial

HI,
I want to create a hack (memory hack) for an online game, mmorpg, I want to hack the client of the game to open the gm section and to buy items from it, I am familiar with VC++ and done some projects generally database projects, I need a tutorial, not the code, but detailed on how to hack the game eg. I have to hack the exe of the client or some dll? the game is knight online. I need to do something like cheat engine?

Thank you