Coupla things. On most small planes, the ignition system is completly seperate from battery/electrical system.

There will be a switch (perhaps a key) labled "MAGS" with positions OFF-LEFT-RIGHT-BOTH and perhaps START.

The battery switch is usually called the MASTER SWITCH.

There may be a fuel boost pump switch. There is also a FUEL SELECTOR valve labled OFF-LEFT-RIGHT and sometimes BOTH.

There have been enough movies where they got it wrong that I should mention that you pull the trottle all the way BACK for idle. To shut down the engine, you pull the red MIXTURE lever/knob all the way back and wait a few moments for the engine to stop and then turn the MAGS off. This runs the engine dry of fuel so that it can't "kick" if someone moves the prop.