The mechanical connection branding matrix of World of Warcraft is an engineering drawing bought from a vanity businessman in Dalaran. You must be an engineering major to learn it. The purchase cost is odd coins, and odd coins are epic copies that may fall. The purchase route is as follows:

The first step is to log in to the game and return to Dalaran with the hearthstone.

The second step is to reach Dala and run along the route.

Step three, you can see a vain businessman in the corner.

The fourth step: vanity merchants click the right mouse button to trade.