I wish I had more pictures of the LED tracking unit, but there is plenty of info at Redroks website. The unit uses LED's to measure the position of the sun and tells the linear actuator how much to move and where to position the panel. It's really a slick little unit, and at a great price.
Go to http://www.redrok.com/led3xassm.htm#led3xforsale
to purchase one if you want to try this yourself. There are plenty of pictures of how other folks have mounted them at http://www.redrok.com/electron.htm#led3x
. I put mine in an empty peanut butter jar and mounted it to a 2 x 4. I attached the 2 x 4 to the side of the unit to get the LED tracker up above the panel to give it an unobstructed view of the sun.