orage top up light on,how do i top ut to get heating on?

my little jug lights up orange, heating and water on. due to being in rented accom, no instructions! am i causing any danger or dammage, and can u tell me how to fill please? have opened tap, but no joy. heating and boiler just stoppwd. got a little one and we are both cold. hope u can help, thanks. model vokera, option boiler. wont ignite after i just put it on. it only has a round tap underneith, that says open and close, it stays slightly open for the hot water pressure to work. did leave fully open for three hours to see if this would take off orange light!