Start the gyro and let it come up to speed.  You can bring it up to speed faster if you initially give the gyo a spin by hand when you turn it on.  The gyro should be balanced so that it will remain in the same plane when spinning.  You can then rotate the gimbal system and observe that the gyro axis does not move.  Note that there is a thumb screw that will allow you to pin the outer and next inner gimbal together if desired.

To show precession, add one or more of the masses to the front or the back of the axis "arrow".  These masses have a small inserted magnet that will keep them in place even if the axis flips 180 degrees.