Step 1: Assembly
After removing the inside metal plate, I used this template to drill holes to mount the LED matrix. The LED matrix has 8 mounting screws on the back of it. The mounting template shows the placement of the 8 screws on the back of the LED panel as well the cut-out needed for the LED panel header and power cables. Use (8) 4-40 x 5/16″ pan head screws (not included in the kit) for mounting.
Here's also a generic mounting guide for the kit.
You'll also need to cut a rectangle cut-out (also in the above template) for routing the cable to connect the LED matrix to the IOIO board.
Then it's just a matter of connecting the ribbon cable (included in the kit) from the IOIO board to the LED matrix and mounting the board inside the case (hot glue used in this case).
The whole project is open source. If you can code in Java, then you can leverage PIXEL's SDK to add in new functionality.
PIXEL developer information ==> Link
Source code for Android ==> Link
Source code for the PC application ==> Link
Special thanks Ytai Ben-Tsvi, creator of the IOIO board, for all his invaluable help on this project and to Roberto Marquez who developed PIXEL's PC application.