Log into your Blogger account and click on the ‘Template’ tab
Once there, click on the ‘Manage’ button in the top right area.
NOTE: when I originally wrote these instructions, the button said “Manage” but now I believe it says “Backup/Restore”.
Before continuing, download your current template and save it somewhere on your computer (just for backup). Then when this is done, browse your computer for the new template.xml file and upload it.
That’s it! You should see your new template load in the small preview window on the template page. Visit your blog to check!
AFTER INSTALLING YOUR NEW TEMPLATE YOU WILL NEED TO INSTALL YOUR HEADER IMAGE!