The kit can be programmed either from an external programming tool or through a USB bootloader which is pre-programmed on the device. The bootloader is evoked by pushing the push button (SW0) during power-on, i.e. push and hold the button and hence connect an USB cable to the kit. Programming can be performed through the DFU programmer FLIP. How to use FLIP to download new firmware to the kit is described in-depth in the appplication note AVR1929: USB DFU Bootloader for XMEGA A3