How to delete a template, (Astra) and get back to a blank website to start over?
Deleting a theme is as easy as going to: Appearance > Themes and selecting a new theme for your site. Then, after you’ve changed your theme, hover your mouse over the old theme, select, “Theme Details” and then click the “Delete” link in the bottom right corner.
But, if you’ve imported one of Astra’s starter templates, and allowed it to also import the associated images and create pages and posts… well, that’s a little more tricky.
You can, of course, go to the Pages menu and delete all the pages it created during the import process. Then, go to Posts and delete all the dummy posts that it created. Then, go to Appearance > Widgets and delete all the widgets. Go to Appearance > Menus and delete the menus. And finally, go to the Media Library and delete all the imported images.
Better still, if your site is hosted by a Managed WordPress host that provides nightly backups, you can simply restore your site from an earlier backup. Visit your web hosting control panel (not your WordPress admin area) to restore your site from a backup.
And finally, you can also install a plugin like the popular WP Reset, which quickly resets your site’s database to the default installation values — without modifying any files.
It deletes all customizations and content, or just the parts you choose, like theme settings, for example.
WP Reset does not, however, delete any media files, plugins, themes, or uploads. It also preserves your site title, WordPress address, site address, site language, and search engine visibility settings. And, the currently logged in user will be restored with the current username and password.
Hopefully one of these methods will work best for you!