What are these 4 slots? The middle at the end is for power? What about the other 2 at the end and the 2 at the left side?
Offtopic: Its funny how much such pcb's remind me of cities. Streets, flat buildings, oil containers, foundries with chimneys...

Nearest us - USB, Power, Power & Power. 3 connection options depending on how you intend to power it.
Left side - CAN Bus header connector, and what looks like a cooling fan power connector.