As you enter terminal 3, stay right (venture right and behind of the Emirates Ticketing Desk which only serves full fare passengers). It's on the right off the main corridor that runs the length of the terminal building. Once there, you will find check in desks for staff and stairs leading in a basement of sorts where all the Kiosks are to issue tickets and computers to check the portal etc. If (big IF) you are lucky, there might be a nice ground staff to help you if you need help with tickets etc.
Basically, you would think that Emirates do not want us to find our way to Staff Travel as it really is hidden in the depths of that new terminal. Weird.
I hope that made sense...