The fuel filter is bolted onto the back of the floorpan. To change it you just need to put the car on axle stands and undo the two jubilee clips holding the hoses on, unscrew the self-tapper that holds the retaining band and pull it away. Make sure you fit new one with the fuel flowing the right way (note the direction of the arrow on the original before you take it off!)
If you're planning on doing any more work yourself then the Haynes manual is a worthwhile buy...