Its always a good idea to backup your blogger blog’s template before making any changes to it or before uploading new template.
How To Backup the Blogger Template
1. Login to Blogger. Then on your dashboard, Go to Layout > Edit HTML.
2. On the Edit HTML page, click on the Download Full Template link and save the XML template on your computer.
That’s it. You’ll now have a file with a long and complex name like, 12332323232p23p23p.xml on your computer. This is the complete backup of your existing blogger template. In case of any errors, you can easily install it again and your blog will be back to its previous layout.