Britony Combi 80 by Chaffoteaux?

Our combi boiler has packed in, we have no heating and hot water, the pressure is at zero, I've been trying to find out how exactly to raise the pressure but I'm not very technical and don't really understand all the terminology. I have a 'filling loop' which I know I'm supposed to use to raise the pressure but I can't fathom where it's meant to go. I know nothing about boilers and my landlords are ***** so won't come and sort it, can anyone help an idiot fix their boiler?