IMO items that have no info - especially when their site doesn't even have the info - is pretty **** poor. That alone has unfortunately often caused me go elsewhere. (And since I had a budget of $millions per year....)
They don't even state if it's SPST or SPDT nor how the LED is connected
If 3 terminals per side, it's probably a DPDT switch with the center pin "common" with one end the NC terminal and the other NO (normally closed and open respectively).
While simple enough to experiment for the switch side (ie, center pin to either of the outer pins), on the LED side it should be +12V to one side and GND to the other, but neither to the centre if it is a DPST switch. That's what we call a short circuit.
So test with a DMM, else ensure a suitable fuse or lamp to limit current if testing a load.