Forget about the magneto switches - they're not connected to anything. If you're in the Hurricane or the Spitfire make sure your radiator is in the fully open position before you do anything else.
Make sure throttle and prop pitch are at zero. Now you've got to grope around with your mouse to find the fuel cock. On the Spitty look at the bottom edge of the instrument panel, just to the right of the joystick and you'll see an up and down lever.
That's the fuel cock.
On the Hurri look down to your left in the area of the throttle and radiator control and you'll see the er...thing, around there...er...somewhere. ( yes, I have forgotten )
Once you've got your radiator and fuel cock open give her a little open throttle and press I.
Once the engine is running you'll have to wait a couple of minutes whilst it gets up to temperature.
Remember to put prop pitch back up and then.......Vrooomm.....hopefully