Once you want to get any more complex stuff going, you'll need a helper library to manage stuff like the internal temperature sensor, LED matrix, or Bluetooth connection.
To make your life easier, we've written up a wrapper library that manages all this stuff for you.
You'll also need to install some helpers.
Open up the Arduino library manager:
Search for the BLEPeripheral library and install it
Search for the Adafruit GFX library and install it
Search for the Adafruit Microbit library and install it
We also have a great tutorial on Arduino library installation at:
Once you've re-started the Arduino IDE you should see the library examples appear in the File->Examples->Adafruit_Microbit menu