To program the Teensy++, you'll need to install the Teensy Loader application via instructions available here.
Once the Teensy Loader is installed, download the stable version of GliGli's firmware here:
Unzip the firmware zip file and locate the .hex file within the resulting folder - this is what we'll be uploading to the Teensy++ …
Connect the Teensy++ to your computer via micro USB cable and launch the Teensy Loader application.
Press the reset button on the Teensy++ and then click the grey Open Hex File button in Teensy Loader.
Choose the p600firmware .hex file, and then click the curved arrow Program button.
Once the programming process is complete, disconnect the Teensy from your computer. We can move on to modifying the board.