Google Drive - restore previous version of file.

Open the document and click on FILE. Scroll down to Version History

and select "See Version History"

The list of saved versions of the document is displayed in the column on the right

Select the version of the document you want to view and it will be displayed in the document

window.

When you are viewing a previous version of the document, you will have a

"Restore this Version" button available at the top of the window.

Choosing to restore the version creates a new "restore point option" for the current document.

if you click the MORE button on each available version, you can name the document versions

for easy recall.