I have been working on a tutorial, but it’s unfortunately nowhere near complete, and I will be away for the next week. I suggest using the Modular Sensors library on GitHub, where there’s an example called logging_to_EnviroDIY. This is formatted to log to data.envirodiy.org, where you can set up a hosting site for free.
The catch is that it has a lot of library dependencies, which could be difficult to set up depending on your Arduino background.
Because you are using Hologram, line 106 will be:
const char *apn = “apn.konekt.io”; // The APN for the gprs connection, unnecessary for WiFi
The Modular Sensor sketches have a built-in “sensor testing mode”, and when you are in logging mode, watching the serial monitor, the sketch will give you
the “response code” for your internet connection, which you can look up to see if you have success (201 is the winning response: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes).
I’m attaching the tutorial text that I have done so far. It’s really in first draft mode, but I hope it can help you.