To fully starts using micro:bit and its functions to interface with the world, you will need to learn about its edge connector. This can be used to connect to external circuits and components. However, in order to use the edge connector, you will need extra equipment like crocodile clips/banana plugs or other external PCB connectors (1.27mm pitch).
There are 5 rings to connect with 4mm crocodile clips/banana plugs - 2 of them (3V, GND) are connected to the micro:bit power supply and the other three can be used for general purpose input/output using both analog and PWM (pulse width modulation) and touch sensing. The smaller 1.27 mm strips allow you to either connect to different parts of micro:bit or which you can use for your own purposes.
developer reference: https://tech.microbit.org/hardware/edgeconnector/