How would you make anything radio controlled?

This is almost always accomplished through the use of electronmagnetic waves transmitted from a: 1) "Transmitter": in the form of a box with two or more joysticks and switches or a "gun grip" with a trigger and wheel. 2) To a "receiver": small box that resides in the model which receives electromagnetic waves from the transmitter on certain frequency range. 3) Which controls "servo motors" (for physical movement such as turning the wheels or opening the carburetor) and/or "regulators" (for in/decreasing the flow of electricity to electric motors)