Want to set up my SolisCloud app and haven't a clue how to do it!

It will only connect to a 2.4ghz WiFi network so if your WiFi router is broadcasting a 5ghz network then you'll need to change the settings on it or connect it to the 2.4ghz network.

Given your level of knowledge here Gorteen, it would be fairly difficult to step you though this in fine detail. That said, I'll explain the rudiments what silver_sky was talking about

Most wi-fi routers can send and receive radio waves, at two different frequencies.

1. 2.4Ghz radio band
2. 5.0Ghz radio band.

The 2.4Ghz is the older band and it had more "penetrating power". What I mean by that is that if your router is in the front room, the 2.4Ghz frequency is more likely to get to the kitchen or out the back garden as while it's slower, it's better at going through walls windows etc. The 5.0Ghz band is the newer (10 years old now ) and a faster frequency for connecting on. The downside with 5.0Ghz is that it struggles to get through even partition walls, and solid cement blocks will stop it dead.

The inverter typically will only connect to the old 2.4Ghz band. Your Wifi router usually has a login and you can log in there and setup the names of your wifi. Most people set the 2.4 and 5.0 bands the same name and let your phone decide what to connect on. However, you can specifically call them individual names like

MyWifi_2.4

MyWifi_5.0

And then when you connecting your inverter, you can specify explicitly the ID of the wifi which is 2.4Ghz. As for how to do that, I'd get a tech savvy friend/relative to sort you out.