@KasaUser The HS210 will work fine in a single application. If power comes from lamp end switch, it powers one or the other of the "Traveler'' contacts and that powers the circuit. '

@ctrl77 Have you solved the porch light problem? You should have a white Neutral wire connected. Here is a drawing of the switch. (attached)

After searching the internet and finding no schematic or block diagram, l opened one and drew a rough schematic/diagram of the workings. This is the HS200 Schematic and pictures of circuit board