not sure really…

RE: not sure really…

Not at all a stupid question. Here goes (in reverse order) –

Q2 – Yes (but then it is my job!)

Q1 – Boeing (and Airbus) aircraft have a starter motor attached to the side of each engine. Unlike your car, instead of using electricity to turn them (although most turboprops use electric starters) they use bleed air. Most commonly this is taken from the APU but if the APU is unserviceable you can plug in ‘air start units’ into the underneath of the aircraft. We have 3 plug in points on the underside of the 757 but need at least 2 air starters attached to give enough ooomph. Assuming the APU is available (and the APU bleed source is switched on) you turn the relevant (left or right) start switch to the start position and bleed air is directed from the APU to the starter motor. This will spin up the spools in the engine. When a certain rotational speed is reached the fuel selector is turned on which not only throws in fuel but also turns on the igniters. When the engine fires the engine speed will accelerate to ground idle and the starter motor and the igniters will automatically switch off. In a jet engine there is continuous combustion so there is no need to have the igniters switched on all the time. The next engine can either be started using APU bleed air again or using bleed air from the first engine you started.
The most modern aircraft have fully automatic start up sequences so having hit the start button the fuel and ignition would engage themselves at the right time. Also I am led to believe that the 777 has such a powerful APU that it can start both engines at the same time without even having to turn off the air conditioning!

Hope that helps.