You will need a fitting like this (just a quick internet search to find a sample). A female inverted flare fitting that corresponds to your tubing and nut size on one end with a 5/16" hose barb on the other end. Your local auto parts store should have one or also try NAPA. Then your can have your flexible hose connection between the tubing and the fuel pump barb fitting.
https://ustoolhub.com/inverted-flare...saAocyEALw_wcB