A part of the review has been auto-translated.
The operation is simple: put 5 V= on the green connection or use a micro usb cable to power it. The start the eWelink app to setup wifi. It than works fine but not all as I intented. It seems the be a secret how the app talks to the device. I had hoped to be able to make my own connection using a Raspberry Pi. That way I wished to be able to make things happen at home while on the road. But the app limits to operation within the own WiFi network. Apart from that it is not clear to me why I need to register with the producer to be able to use the app, and why so many permissions are needed for the app to run. So alltogether: the device works as intended by producer, but I expected to be able to do more with it.
I ordered 3 unit. setup is very easy with EWelink app. it’s working very well. I recommend it