Don't touch the one on the "bulb/prop shaft", that's the gear shift pin. You won't be happy if that comes out. Usually, the plugs are right under the cavitation plate for vent, and below the prop shaft for the drain/fill.
First is drain plug.
Probably an allen head set screw.
Top is fill and the vent for escaping air.
The very bottom is the drain.
The slotted screw is a pivot pin for the shifter.DON"T TOUCH!!