Using this 4 - Channel Relay for Micro: bit is easy. First, connect the relay module to your Micro: bit. Make sure the input voltage is set to 5V as specified. You can then use your Micro: bit to control the 4 relays. When it comes to the load, it can handle 3A at 120VAC or 24VDC. Remember, the working mode is NC/NO, so set it according to your needs. As for maintenance, keep it in a dry and clean place. Avoid exposing it to extreme temperatures or moisture. If you have any problems, refer to the user manual available via the wiki link.