Yeah I don't have a specific tutorial but here's what worked for me:
I did Tools-->Port-->(change this one by one and hit upload).
That should help you find the successful proper serial port you connected your arduino to on your computer.
After that this is what the example cURL command was that I sent to the Heroku REST API that successfully POSTs and shows up on my device screen (I just tested it now too):
curl --location --request POST 'messaging-thing-api.herokuapp.com/api/messaging' \
--header 'Content-Type: application/json' \
--data-raw '{