Just replaced the petrol filter on my
MK4 Ibiza 1.8t (2004) and altho Adam has done a fine job of explaining the process here's how mine went;
I didn't take the fuel pump fuse out.
Filter is just in front of o/s rear wheel.
I used the jack and an axle stand to gain some clearance to work with.
Use a Phillips type screwdriver to unscrew the plastic clamp around the filter and unclip the handbrake cable from it's hooks as Adam said.
The filter is now loose and being held by the fuel pipes either end of it.
Have a container underneath the filter with some rags as when you disconnect the pipes some fuel comes out but mainly from the filter itself in my case it was very little and certainly didn't spray everywhere!
The connectors of the pipes have an indentation that can be pressed in with fingers and with a bit of brute force and ignorance both pipes will come away from the filter!
Empty filter into container then get new one and offer it up to the pipes, there's a direction arrow on the filter it shd point towards the front of the car, push on both pipes and you should feel them 'click' over the lip on each ends of the metal inlet/outlet of the new filter.
Reconnect plastic bracket and put handbrake cable back in it's hooks.
Job done!!
However as I said this is how mine went so I hold no responsibility if anything goes wrong, good luck hope it helps!
Steve.