Basic README documentation is missing from module

Problem/Motivation

Great job on bringing this module to the Drupal marketplace. Unfortunately, it's not clear how to get it to work. I'd ideally like to see this module working so that when a Drupal Commerce order has been placed, an APN is sent off via push_framework/pf_onesignal to an iOS app.

Steps to reproduce

I've done the following.

1. I've created a OneSignal account and followed all instructions at https://documentation.onesignal.com/docs/ios-sdk-setup to enable my iOS app to receive notifications. I've confirmed that I can send a notification to the iOS app and I can see it as well. Success!
2. On the Drupal side, I've implemented push_framework, pf_onesignal, and danse with Composer. I can confirm that Danse core and submodules danse_config, danse_content, and danse_log are enabled.
3. I've edited the content type that I want to create a message from and enabled "Create Event" on node create and publish.

Unfortunately, I'm unable to send a push notification from my Drupal site to OneSignal in order for it to show up on my iOS app.

Proposed resolution

We really need basic instructions to get this module working and sending notifications to pf_onesignal or OneSignal. If for example, a simple "how-to" page to send a notification alert when a node is created would be super helpful.

Remaining tasks

Add help pages and get started documentation.