citroen zx 1.9 diesel how to change the filter please thanks

Several types eg roto,cav or bosch If its the screw on type just remove old filter get new filter & fill it to the top with fresh diesel screw it back on & fire up the engine no need to bleed this type.If its paper element undo the filter housing remove old filter clean out filter housing fit new filter undo small 8mm bleed screw & either squeeze priming bulb or press lift pump primer button till fuel with no air bubbles comes out of bleeder lock up bleed screw & fire engine.Always make sure rubber O rings r fully seated or next time u start the car u will have to bleed it again as fuel will run back in to the tank & system will pull in air.