Create New Sales Order using REST API POST method from HTML Form Submission

I’m completely lost and in need of help. I’m self taught in everything I know about coding so please bear with me.

I currently have one server with multiple sites because I want to keep the domain used for ERPNext separate to the domain used to access the website. I am trying to use REST API to POST/create a sales order when a form is submitted.

I have no idea what to do. I got post request to work when I used Postman but I’m not sure how to add it to my custom app.

Maybe this can help you to get going. Am not a developer so can’t assit you with it.