I've tried to search everywhere to see some step by step examples and I can't find any full examples. 

Would it be possible if someone could provide a link or post steps below (screenshots?) that I can follow to use Javascript (from Forms) to pass a few values to workflow to then set up and run an HTTP Request (server-side) with those values attached to the JSON payload via HTTP web request and then pass back the response JSON to javascript?   I would do it directly from JS but there is basic auth attached to the request that I don't want the world to see.

Thank you in advance!