I'm using this in the switch box for the Family Room lamp in front of the West Window.
I programmed the shelly device using the Tasmotizer software along with a current Tasmota.bin image and the hookup diagram below. I used a Sparkfun FT232 programmer which has 3.3 volts as an output.
(above) Programming Tasmota using USB
(above) Configuration. Tasmota has a Shelly dropdown to do this when selected.
(above) Typical wiring for a single pole switch.