How to post/send data to webhook (& store locally)

Plasmic Studio Questions
1

  1. I’m trying to figure out how to add my webhook. I need my form field group to post data to Make. I see an option to fetch, but NOT to send. I see an option to send via the “publish” button, but when I do that, I get an error code (400).

  2. I’m trying to save data locally between 4 pages, before submitting all user input at once on the final page. Everything I’ve tried has failed.

If anyone has significant experience, I’d be willing to pay for a tutorial on setting up the backend of my app. I’ve had a hard time finding a coder who’s willing to interact with my no-code front end