How to control the loudspeaker plugged into a car on and off by rf remote controller

My dad would like to plug a loudspeaker into the trunk of his car and wanted to control it by remote controller. He was wondering if it could come true because he wanted to use loudspeaker to listen to music when he went out for picnic with us. He just searched from the internet, then he chose Model 0020003(S1L-DC12 & C-2) from one remote control supplier.

It is the wiring procedure which the supplier shows to him. The red wire from the loudspeaker is connected to the C terminal of the receiver and black wire from the loudspeaker is connected to the negative electrode of the power supply. The positive wire of the supply power is connected to B terminal and positive electrode of the receiver. The negative electrode of the power supply of power supply and receiver are connected together.
When we press the button1, the loudspeaker turn on; when we press the button 2, the loudspeaker turn off.