What kind of remote control and receiver are you using?
For a general RC control you need a channel splitter, that separates the PCM signal into distinct channels. This splitter can be provided in hardware or in software. Then listen for a signal on the selected channel, and turn your buzzer on and off depending on the signal level.
If your buzzer is an active buzzer, i.e. yells when power is applied, you simply turn the buzzer supply on and off. A passive buzzer (loudspeaker) instead needs a wave signal, as created by tone(), which you turn on with tone(pin, freq) and off with noTone(). You may need an amplifier (transistor...), if the Arduino output is not powerful enough to drive the buzzer.
Thanks for your answer
If its PPM or SBUS protocol I guess it'll be a little more complicated, but lets say my receiver has PWM,
Which means that I can connect each channel individually which is much easier..
I think you misunderstood me when I said buzzer (my bad)
Its a Bicycle Horn device -> http://www.banggood.com/Wholesale-7-Sounds-Ultra-loud-Electronic-Bicycle-Bell-Bike-Horn-Siren-p-34132.html
That has a button, I think that the button is just a jumper between two points in a circuit inside this HORN.
Is it possible to close a circuit with arduino code ?
Sorry my questions is super basic