Your mouse is the control stick. The neutral position is the center of your view display – denoted by the dot in the center of your heads-up-display (HUD). Moving the mouse away from you pitches the plane down, moving it back pitches the plane up. Left and right inputs roll the aircraft in the corresponding direction. On the ground at speeds up to 100 kts, nose wheel steering guides the aircraft.
To take off for the first time, select 20 degrees of flaps (press H twice), then press the full throttle key (the 4 key on the main keyboard). Keep the mouse in the neutral position until you are moving at about 140 kts, then pull the mouse about two-thirds of the way down the view window. You should pitch up and lift off the ground fairly easily. Gradually move the stick closer to the neutral position and let your airspeed build – don't move it back to neutral too quickly or you will end up back on the ground again! As your airspeed passes about 250 kts, raise the flaps (press Y twice) and landing gear (press G). Congratulations, you're flying a multi-million dollar jet.