Have a look at: Trace to Outline, Panelization without space; Panelization with space; in: [https://jlcpcb.com/capabilities/Capabilities](https://jlcpcb.com/capabilities/Capabilities) and: [https://support.jlcpcb.com/article/49-pcb-panelization](https://support.jlcpcb.com/article/49-pcb-panelization) Draw the outlines as rectangles with their adjacent edges overlapping. V-cuts must extend all the way across the board forming a grid so there can be no T junctions in the cut lines. Don't forget to allow a small amount of space either side of the board outline for the bevel on the board edge due to the V-cut tool.