I'm looking to have a box with 36 buttons (wireless) that sends a radio
signal to a transmitter box that would then "fire" the corresponding
circuit.

The last several years I've been doing a fireworks show with a 36 shell
finale. The last several years I've been doing it analog with 36 sets of
wires, one set to fire each shell. I'm looking to have a box with the 36
buttons and LEDS and then when a button is pushed to have it fire the shell.
I understand some basics but looking for the best and cheapest way to do
this.

On the receiver end I'm probably looking to stay with 12 volt DC supply
powering one box that would have wire terminals not 36 separate boxes.