O.K,
There are two main take offs. The first is for "gas and electric flight". This one is for little planes that are "hand launched". The force or momentum of your hand launching the craft accelerates the planes momentum. This causes lift as well as an decrease in the planes weight as the engine or motor propels the craft. The second is a taxy takeoff. This is a ground takeoff. The wheels are generally steerable by the rudder, or a dedicated servo. If the "TX or Radio" is moved left the plane will steer left. If right, it will steer right. This gives the pilot complete control. It is kind of like an RC car type affect. Second "acceleration or throttle" is applied, and the plane should start to lift causing the pilot to add a little elevator. When this is done the plane should go up correctly into the air.