You should see 5 copper pipes connected to the underside of the boiler, and there will be a 'filling loop' (flexible hose with a ballofix valve on it) connected between 2 of these (namely, 1 is the cold water supply to the boiler {15mm dia}, and the other is the heating return pipe {22mm dia}. Make sure the connections at both ends are tight, and turn 'open' the ballofix valve. The pressure gauge will rise. Turn the valve 'closed' when the pressure gets to 1.0 - 1.5 bar.
Hope this helps.
CMac, November 2010
