Operating the Roksan Kandy K1-A integrated amplifi

I bought a used integrated Roksan Kandy (not the LIII)and would like how the lights work in the front-it panel. It seems that when the light is red the unit is on; so I wonder how to leave it "off" without having to actually switch it off using the rear power off toggle switch. Also, I would like to know how the rear "preamp input" works.