I am assuming you have a standard, key start ignition switch. Insert key turn one click clockwise turns on power to the engine, one more click clockwise powers the starter. The second click is against a spring so the key will move back to the first position?
You need to know or figure out the connectors on the back of the switch. The generic answer:
1. Power from the battery. Yes this usually comes from a battery selector switch.
2. ON position. First click of the switch. Battery power from 1 is sent to everything connected to 2. Of course the ignition system would be on this circuit but probably includes other circuits like fuel
, gauges, meters, panel lights, etc.
3. Crank position. Second, momentary position. This sends power to the starter solenoid and is active only as long as you hold the key.
If this is all sounding like Greek then you might want to get someone to help take a look at the system with you.