Neil,
The connectors are (from left to right):
1. Type C USB for powering the Raspberry Pi
2 & 3. Micro HDMI ports for connecting HDMI displays/Monitors/TV. There are two ports for dual displays
4. 3.5mm TRRS audio jack used to output the audio from the Pi.
?
?
73,
Ragav
VU3VWR
