/diy/ - Do It Yourself

Hey, does anyone here know how to use solidworks? I'm trying to make a wing for an airplane, but I can't figure out how to "fillet" the wingtip. I want it to have a smooth edge. I've used a cut-extrude to get the right shape, but I just can't get the edge smooth. I've tried everything in the fillet tools and following YouTube guides on boundary surface but still with no success.
Pic related, it's the wing. Basically instead of the edge being |_| shaped I want it to be a smooth U.

Link to the part file here in case you need a closer look at the thing. https://filebin.net/oaextjt33c9groqv