How to Install a Custom or Premium Blogger Template
Sign in to your blogger blog and head to “design” => “Edit HTML”
Before uploading new template backup your previous template.
Now browse your computer and select and upload your desired template.
After this process, blogger will ask whether to keep or delete your widgets.Take your choice (see screenshot)
Now preview your blog and if everything is fine hit ‘Save Template’ button.
That’s it, your new template is live now.