you have:-
-2 electrical plugs to remove, one towards the front of the car at the bottom and one on top
-The fuel filler hose and breather to undo
-2 fuel pipes to undo which are located on top, mark one of these tubes and the rubber hose with tippex to make sure it goes on the correct place upon refitting
and
-finally the 2 13 mm tank strap nuts to undo.
A note with these is to spray them with a lub as these are pain in the arse if they break because the bolt is captive as i found out
The main thing first is to make sure the tank is empty and dont smoke/create sparks near it as its highly flammable. I found the easiest way to drain was to twist the sender from the bottom of the tank into a suitable container. Not all tanks have the sender in the bottom so may have to be drained from the filler tube.
If your replacing the tank, make sure you get the right one too as there are about 2 or 3 different types just for the hatch