The board

Dimensions

Dimensions:60 × 60 mm, four screw holes

Connectors

HDMI type A, USB-C 2.0, micro-SD with card detect, 4-pole audio jack with switch, speaker connector, gamepads/keyboard/mouse on Bluetooth

One user button

Power

5 V from the USB-C input

One thing to know before plugging the board in: USB power alone is not enough for the nominal case. A USB port advertises 500 mA by default, and the board negotiates nothing on its CC lines. Either the firmware measures those lines to find out what is available, or power comes from elsewhere.