I can help start with the basics...
There is fuel line that runs into the gas tank that should have a filter on the end of it. The fuel is always at the "bottom" of the tank, no matter the angle. The filter has enough weight to it to keep the end of the fuel line at the "bottom" of the tank too. You can normally see that it is doing its job once you take the gas cap off. It should be connected at one end to pass through the tank and to the carb and the filter side of the hose should flop around as you turn the saw.
... just a note, the less fuel the better.