Instructions
Start the game and go immediately to the graphics options. Make sure you have the scenery option set to dense or higher and the box for animations checked.
Navigate to the traffic options and make sure the traffic is set to at least medium, or the jet ways will not work.
Select an aircraft to which the jet way can attach. It must be a large aircraft, like the 737, 747, Airbus or other commercial jet. The jet way will not attach to smaller aircraft.
Park the aircraft in the correct spot on the ramp. The front wheel should be on or very close to the yellow line that guides you in from the taxi way, and the nose of the aircraft should be close to the terminal building.
Press "Ctrl" + "J" to activate the jet way. If you have a slower computer, the animation may move very slowly, so be patient, but the jet way will eventually align with the plane. If it still will not work, then make sure you are parked in the correct place. Look at the aircraft around you if you cannot get it to work.