Just to be sure you know: this is just a TTN Community forum, not some professional support.
The data format is described in the first manual.
Also, you will need to find a way to disable the confirmation that the device requests: with the TTN Community network you’re only allowed 10 such confirmations per day, so that would limit the uplinks to 10 per day as well. I cannot quickly find that in the manual, so please ask your provider about that.