Restore a Page Version Instructions
Hover to the three-dot More menu on the top right corner of the your site and select the first option Version History from the options list.
A list of versions of the site will appear on the right and the preview of the page on the left: choose the version you wish to restore.
The preview will change to the version selected and if this is the correct version you want use the
Restore this page version button.
The Google Sites editor will ask you if you want to restore this version: if you do use the Restore page button; if it's the wrong version use the Cancel button instead.
Google Sites will tell you the page has been restored.
This feature is available for all Google Workspace editions and personal Google accounts.