Sound Issues

I am trying to make a checkbox system for turning sound on and off within a game. I don’t know the node that I am looking for to make that happen. Any Ideas? Also is there a more detailed tutorial out there about how to set the slider bars values so that it doesn’t just slide for does and it actually only goes to the x defined positions on that slider bar. What to do a contrast and brightness thing as well but that is meh atm.