To program the littleBits Arduino module, you simply connect it to a computer running the Arduino software via USB and connect a littleBits power module to one of the module inputs. From there, you only need to select Arduino Leonardo in the board dropdown menu and the port your computer has opened for it. On a Mac, it will be something like /dev/tty.usbmodem and in Windows, it will display as COMM1 or similar. When your sketch is ready, press upload in the IDE.