The 'line' symbol represents ON, and the circle symbol represents OFF.
As far as the switch terminals, the best way is to use a multimeter/voltmeter OHMs function to identify the two terminals that are connected when the 'line' symbol is in the depressed position. You don't really care what the exact ohms measurement is, when the multimeter probes are touching the correct pair of terminals, the ohms reading on the multimeter will be close to zero. You don't need a fancy or expensive multimeter (I recently bought a 'spare' for $10), but you should have one if you are working with electricity.