You can have a dashboard with your main layout, one that is auto-generated (like the old State UI), one for experimenting, one for admins, one for your wall-mounted tablet, etc.
But when you select “Configure UI” I get a warning:
This dashboard is currently being maintained by Home Assistant. It is automatically updated when new entities or Lovelace UI components become available. If you take control, this dashboard will no longer be automatically updated. You can always create a new dashboard in configuration to play around with.
Are you sure you want to take control of your user interface?
So I always opt out.
Which is true?
Will I loose the automatically updated dashboard or will I still have one?
Go into Configuration > Lovelace Dashboards, create a new one and indeed, you take control of that specific one. The “default” will still be automatically populated
you can add another dashboard…test2.doug if you want more than one. The base dashboard will be left alone and automatically populate with new items.
create a new file test1.yaml and any other dashboards you create in the config folder…and edit them there. The original will still be available at Overview. when you click on the new page in the sidebar, look at the URL of the page…that’s how you show your new page.
To see all the desktops, go to configuration/lovelace dashboards.