It is quite simple… The radio waves are waves of electromagnet magnetic energey, the radio wave is made by sending an oscillating electric current at the right frequencey into an antenna, that antenna creates a radio wave, this is now a Transmission, by adding changes to the oscillation by Amplitude AM (Bigger and smaller signal) we can add infomation such as voice) or we can to the same by frequency FM (how the far the waves are apart). An antenna can also receive the waves and recever elecronics can be used to convert this back into the infomation sent.