Calmate, I believe you Both Need to be at Level 35, and have a minimum of 200 Engineering.
First, Take the quest from Tinkerwiz down in Ratchet, Depending on your Choice or Side, You may have to take it Either a Short or long Distance.
Alliance:
Gnome Engineering: Take the Book to Tinkmaster Overspark in Ironforge.
Horde:
Gnome Engineering: Oglethorpe Obnoticus in Booty Bay.
Both:
Goblin Engineering: Nixx Sprocketspring in Gadgetzan