You don't need to remove the fuel, just turn the fuel tap to the off position, which is the lever in the horizontal position.
Remove the fuel line.
If the tank is full, it can be a bit heavy.
If you have never removed the tank before, you need to open the seat, remove the tool tray, then there is a large wire 'bial' that fits over the end of the frame tube, pull it aft, and then you can remove the tank by pulling it aft out of it's rubber mounts at the front of the tank.