First off I suggest you go here....
http://trainers.hitechcreations.com/ And read abit.
Then it would help to know what your using as a controller,ie mouse or joystick.
In the meantime,go to options,preferences,flight. then enable auto takeoff,this will allow you to atleast takeoff and work on your landings,be sure to not touch controller until you have sufficient altitude to control the plane.
As for landing,lineup a long way out and begin to slow,drop flaps and continue to slow.once you reach 150mph or less drop gear,some planes a capable of dropping at higher speeds but ignore this for now.
When you have both flaps and gear down,use the throttle to control your rate of desent,try to maintain between 500 and 1000 fpm rate of drop.Once over the runway and low allow plane to settle,then flair and touch down.
I suggest using the P38 as it has no torque and makes takeoffs and landings abit easier,when you have that down move to a single engine plane and work on that.
Hope that helps,