Step 9: Array your boards
As previously mentioned, you may array the boards simply by connecting the DO of one board to the DI of the next, as well as the CLK. OE, LE, +5v and GND lines. I simply used trimmed component leads as jumpers.
The biggest factor here is an appropriate power supply. You will not be able to power this via a USB port. A 5-6 volt REGULATED power supply can handle a 6 board array.