Follow this simple guide to install a Blogger template you've downloaded from another site.
1. Click on the Download button and save file to PC (.xml format).
2. Log in Blogger dashboard.
3. Go to Design section --> edit HTML.
4. Click on Download Full Template to Back up your previous template.
5. Upload a template from an .xml file on your hard drive by click Choose File option button.
6. Click Upload button, a confirmation message will appear. Click Keep Widgets.
Now you're done.