First off your hearthstone needs to be on cooldown so set it to Ironforge and use it. After that go to the military ward. When you go inside, walk past the battleground guys and you'll see some tanks go to either oone of the ones in the back or the one to your left. go behind it and right in the middle do auto-unstuck, and you will be inside of the front part of the tank, back up a little and you'll be in the middle of it.