c220d fuel filter

[adrefinish]

i may sound stupid [it has been said] i went to change the fuel filter on my c220d 97, there is a nut on top of the filter housing, do i have to undo this to get the filter off ? is it just a bleed nut ? i also noticed a spring and a rubber washer suplied with the new filter . what are these for and do they go under the nut ? also while i am messing about under the bonnet is there anything else usually forgoten i should look for or change. any advice would be appreciated as i am to tight to buy a workshop manual . best two cars. audi 80 , 190e still missed

worst. mondeo why did ford bother ?