1. You don't.
2. I'm going to assume you mean the symbols on the briefing map:
The yellow circles are waypoints. The lines joining them are the course you should follow
Some waypoint markers are aircraft, bombs or other symbols. They are targets or objectives (the briefing text should make it clear which).
The last waypoint will (usually) be a picture of an aircraft in profile with the nose lower than the tail. This is where you have to land.
If the first waypoint is a picture of an aircraft in profile with the nose higher than the tail, you will be starting on the ground.
3. The early spitfire and hurricane models had a gravity feed carburettor. Any negative g (pushing the nose down) causes issues with the fuel feed that will cause the engine to play up. If you need to go down in a hurry, roll over and pull the nose towards the ground rather than just pushing it down from level flight.
4. You'll need to use quite a bit of rudder combined with wheel brakes while taxiing or taking off in a cross wind. In the British aircraft the left/right brake balance is controlled by the rudder, so full right rudder combined with wheel brakes will only brake the right wheel.