If you plan on using a standard coin/relic type of metal detector, try the red outline circles first. I've marked 2 of them close together on one of the maps. The green can be a variety of other types of targets. Let me give you from a file, my definition for the possibilities of green marked spots.
Green in general is a color indicator, I use for various other targets mostly archaeological (old ruins or foundations but especially those non-metallic objects such as Indian flints, glass, pottery, carved stone with treasure signs).