Chainsaw Repair

Pulled the carb this afternoon and both fuel(?) lines broke off.  One of the lines has some sort of brass plug in it.  What's that all about?  I'll go to my local chainsaw shop in town and get some new fuel line.  Gotta make sure I get that metal plug back in correctly (I presume it's supposed to be there).  Are there some sort of written directions for this stuff that I can download and print?  Thanks for the suggestions.