These are lightweight modular gridfinity baseplates, which have minimal filament usage and use M3 nuts to magnetically hold your bins in place, they do not have physical perimeters to hold anything in place.

Use M3x12mm or longer screws to connect multiple baseplates together.

Important stuff to know before you print : 

• These baseplates only use magnetism to hold your stuff in place : Only use these baseplates if your gridfinity modules have magnets embedded and are used in a stationary application.
• Make sure your M3 nuts are ferromagnetic : These baseplates rely on the inserted M3 nuts to attract the magnets of your gridfinity modules. This reduces the cost of the build, makes it easier to remove the bins again if you need to and allows the bins to be rotated in any direction without having to pay attention to the polarity of the inserted magnets.
• The tolerances on the holes for the m3 might  be a bit tight, if you cant get the nuts in use a hammer or a soldering iron.
• Dry your filament. These baseplates have a high potential for stringing
• Make sure your bed adhesion is strong, these baseplates are prone to warping