After installing now you can start for the basic setup.
Go to Plugins section and make a search for PWA
link: administrator/index.php?option=com_plugins
You will see the Plugin with title : " System - PWA Progressive Web App "
Click on to the title and you reach to back-end of the plugin for setup.
As you see there are tabs, tabs will help you to setup faster.
- Plugin
Version information - Start
The Start URL is required and tells the browser where your application should start when it is launched
Start URL prevents the app from starting on whatever page the user was on when they added your app to their home screen.
Your Start URL should direct the user straight into your app, rather than a product landing page.
Think about what the user will want to do once they open your app, and place them there.
Additionally, you can add query parameters to start url to control the pwa visits, as seen below, ?utm_source=pwa - Naming
The section to name your app - Theme
Color and design settings section of your app - App Icons
The section where you will upload the icons of your application - Apple Touch Icons
The section where you will upload the icons of your application for IOS devices - Shortcut Generator
App shortcuts help users quickly start common or recommended tasks within your web app. - Pre-loader
You can enable preloader. A preloader is animation that shows for page transitions - Push Notifications
You can add push notification id at this section - Extras
In this section you can add custom CSS and customize any design easily and you can add custom JS without opening the core extension files.