1. Login to Blogger, and on your Blogger Dashboard, click the Template.
2. Click the Edit HTML tab to edit XML .
3. Click the Download Full Templates link and save it to your computer.
Make a note of the filename and where you saved it in case you need it later!
4. Unrar or Unzip templates files you downloaded from Google Drive, Archive.org, Box, or Copy.
5. Back on the Edit HTML page, click the Choose File button.
6. Navigate to where you saved the unzipped files on your computer, and double-click the one that ends in filename .xml.
7. Click the Upload button.
If you already have some existing widgets on your Blogger blogs, you may get a warning message asking whether you want to keep them or delete them. If you want to preserve the work you've done before, click the Keep Widgets button. If you don't need them anymore, click the Delete Widgets button.
When the upload is completed, you get a message at the top of the page that says Your Changes Have Been Saved.
8. Click View Blog button to ensure that your blog looks the way you want it to look.
You may have to remove or move some page elements in order to get templates to display properly.