how to get an unofficial WiFi Shield to work?
Somewhere it should say this: It is really really difficult to implement enough of the TCP/IP stack on an Uno to handle talking over the Ethernet.  In other words, the shield is doing almost all the work.  As such, if you don't have any documentation, using this Ethernet shield will be difficult.  That said, it looks like this shield is using an ESP8266 which IS widely documented. And if you search around, can even find people creating Arduino / ESP8266 software.