Just two heavy terminals? Assuming you have an alternator, being a 90 it should have, then you should have the more complex switch and resistor etc to prevent alternator damage if it's switched off with the engine running. The heavy terminals should break into the positive feed to the battery. DO NOT connect it to positive and negative as this will short out the battery, the resulting fire might be difficult to explain to your insurance company. Position of the switch depends on what you want to use it for, if its for competition use then the read the relevant regulations.
But if it has four heavy terminals then it can disconnect both positive and negative ......
ZD
