You will need two good flexible fuel line clamps [ Sealey make some neat ones]to shut off the petrol lines leading to and from the filter. ItS usually a small silver cylinder with 2 spigots at either end [ YOUR NEW ONE WILL BE A GUIDE] . The fuel lines are held on with small jubilee type clips with Phillips head screws. Once clamped the clips are slackened off the the lines are pulled off. Expect a little petrol spillage from the filter body when you first slacken off the clips but that should stop after a few seconds -if not check the fuel line clamps are tight enough. Replacement is the opposite of removal but MAKE SURE THE FILTER IS ON THE CORRECT WAY ROUND !! there is usually a large arrow marked on the body to indicate the correct direction of flow [ check the logic-is the fuel coming out of the filter ultimately heading towards the engine?] The fuel filter itself is flexibly suspended in a frame with the fuel pump and you loosen off some the clamp blots to remove the filter-- it,s pretty obvious once you remove the plastic cover over the assembly- don't over tighten any of the cover nylon nuts as they are naturally self locking and you will easily strip their threads
OK they may be crimped clips- they are "one use only" type clips that are put on with a special tool - if so they can be easily replaced with the appropriate size of screw[jubilee type] clip. They may be the earlier banjo type union - basically that's a hollow bolt that screws into the filter end + ring ended pipe and a couple of washers. The important thing is to renew the washers. The new filter may or may not come with them.