One challenge to edge-gluing boards into panels is keeping each of the wet glue joints from sliding out of position. I’ve found that a few pieces of scrap plywood solved the problem for me. I cut a 1/4″ x 1/4″ centered dado across each of these to allow room for glue squeeze-out. When I’m assembling my panel, I use C-clamps to secure two of my little clamping cauls above and below each glue joint. They align the boards and help keep the panel flat.