If its the first time, it can be a hard to pull the tube. I would place a small piece of square wood block under the rear tank so you don't have to hold the tank in a lifted position. Then, slowly work the tube loose with two hands and possibly a plier to hold one side.
The fuel line? There are two white clips at the top of the line. Squeeze in and pull the fuel line off. You will loose an ounce or so of gas so be ready for that. There is also an electrical connection you need to unclip.