The 25 LEDs are used to display simple pictures and messages. The micro:bit is can detect its inclination and movements with the onboard accelerometer, has a built-in compass and can communicate with other micro:bits via Bluetooth. Additional actuators and sensors can be connected with crocodile clips via easily accessible pins. With a little handicraft you can even turn the micro:bit into a moving robot.
Programming the micro:bit using MicroPython is easy. Run TigerJython on a Windows, Mac or Linux system, plug the device to an USB port and flash the device by a menu option. Then programs are edited with the TigerJython editor, downloaded to the target and executed while a terminal Window (REPL) shows errors and runtime console prints. You may even program with smartphones and tablets using our online develepment system.
A short instruction is found under "Getting started". If you are new to Python, you may first work through the "Python Crash Course", otherwise go directly to the menu item "LED Display".