Take a look on around the boiler,
you are looking for a silver braided hose,it maybe already connected to the system or it maybe somewhere near or ontop of the boiler.
one end is connected to the mains water pipe,the other end connected to the central heating system.
Its known as a fill loop.
If the fill loop is already connected,then open the valve on the central heating side first,then slowly open the valve on the mains side and fill to a pressure of 1.5 bar.
Close both valves,fire the boiler up and bleed the air out of the radiators.
paul, March 2012
