To dehydrate watermelon, just cut your watermelon into bite sized chunk.
Or slice it into jerky like strips. We did some both ways today. The thin slices are the ones we prefer.
If you want salted watermelon, just sprinkle salt on the watermelon or leave them alone. It is delicious either way. Place the pieces on the tray and turn the dehydrator on. This is a long process but it is well worth it.
A good idea is to rotate the trays around (bottom tray to the top, etc.) during the drying times. You know it is done when pieces no longer stick to the trays.