Small Engines (Lawn Mowers, etc.): fuel line replacement, fuel tank, featherlite

Question
i need to replace both fuel lines for my weed trimmer. In the fuel tank, both lines were brittle and in small pieces. I bought both sizes and ready to proceed. One is skinny, one is fat. In the fuel tank  one was connected to a fuel filter. Which one?  do both fuel lines  go all the way to the bottom of the tank or does one go in only a little. Which one? Many THANK YOU's for your support. Good health!

Answer
You are describing a Poulan Featherlite Craftsman, etc. trimmer.

The skinny line goes to the filter which sits at the bottom of the tank in whatever position the trimmer is in.

The primer actually pulls fuel through the carb and sends it back to the tank. so it only goes one way.