The car won't crank? That's not an ignition problem... The car should still turn over on the starter even with the distributor connector unplugged. The polarity of the meter connections doesn't really matter, you are just looking for a sign of voltage. Set the meter to read DC volts, if it's not auto-ranging, you want the low end of the scale, like 5 volts. When the distributor shaft rotates, magnets pass by the pickup coil and generate a voltage. That's what you are trying to verify with the meter. If you don't see any voltage (meter doesn't change readings even briefly) then the pickup coil is likely bad.