Assuming that you do not have a joystick plugged in you can do the following:
*Launch the trainer software (but do not power up the screens yet)
*Under Options select “Joystick Axis Configuration” - Select the “Use Keyboard for Joystick”
*Now power up the displays (under the Power menu)
*Press ctrl-UpArrow a few times (i.e. the arrow on your keyboard that moves your cursor up). ctrl-DownArrow slows the aircraft down
From this point I usually just control the aircraft using the autopilot, but you’ll see some other keyboard shortcuts listed under the joystick config page.
In case it also helps: if you want to put the aircraft somewhere else in the world and at a particular altitude, you can hit “menu” twice on the keyboard and the MFD will bring up a special demo mode window where you can change the “waypoint” to wherever you want the plane to be.