Plug the main board, ultrasonic and buzzer blocks into your baseboard like the picture. You can click on the picture to zoom in.
Plug in the cables like the picture - the ultrasonic block should be plugged into P0, and the buzzer into P1.
Plug in your micro:bit with the USB Cable, and transfer the program you have just downloaded.
Test it out! Can you work out what the program does? It should sound the alarm when you get too close - can you work out how to change the code to make it trigger from a further distance?
For advanced inventors - can you add some more blocks to make the alarm more impressive? How about the sparkle block which could flash red when the alarm goes off?