Place your equipment at one common place. Now take one of the brass fittings and connect to the marine gas tank. Make sure that you buy a tank which has a pressure vent system and a special attachment through which you can hook up a line. Any normal marine tank will have these accessories.
Now connect the black plastic connector with the hook up attachment on the marine tank.
The next step is to drill a hole in the cap of the generator tank. Take the cap off and place it on a stable and firm platform. Now place a wooden piece between the cap and the platform and secure it. It would be best if you have an access to a vice.
Fix the drill bit in the drill and slowly initiate the process of making the hole. Remember to go slow and under no circumstances should you use a drill bit of greater diameters. Also keep the drill straight during the entire process.
The second brass fitting goes into the cap opening. If you take care of the dimension, the brass connector should be an exact fit. If it is not, you can use a silicon caulk to shore up the extra space. The second black plastic marine gas fitting goes on top of the brass fitting.
Take the marine ball pump and hose, and with the arrow on it pointing towards the generator, connect the generator and the fuel tank. They should ideally be three feet apart.