The new blogger interface is just a new outlook and upgrade and you can also use this simple tutorial for saving your template for feature use.
You will need to sign in to your blogger dashboard then select your blog which you will like to back or restore.
Now scroll your arrow down and click on “Template“.
Click on the button “Backup/Restore“ in left top.
Now a box will appear like the one below.
Click on “Download Full Template” to
download template and save it in your SD card
Click on the “Browse to Restore” the downloaded Template.
And that’s all….if you have any question feel free to comment.below thanks.