I'm working on a project to cut out paper planes from this book. I'm remaking the planes in Affinity because I can cut out vector files at our local makerspace on the laser cutter/engraver. I'm also trying to color the projects and get them to match the actual planes. In the attached example, I'm coloring a P-80 Shooting Star.
I have a simple question, and no doubt I'm missing something obvious. In the third screenshot, I'm trying to attach two nodes together. They are exactly on top of one another. I select both nodes, hold down shift, and click "Join Curves." Nothing happens, and both nodes are still independent of one another. What am I missing?