1. Launch your browser, go blogger and login into your account.
2. On the left hand side or the second to the last option on the left hand side, you will see Template, Click on Template.
3. On the top right hand corner, please click to backup/restore. You need to Back up your template, so belong is a method to back up your template.
How to back up your template?
1. After Clicking on Template, go to the top right corner, Click on Backup/Restore
2. A window will appear, so to back up your template, click on Download full template
How to install a template on blogger?
1. After clicking on Backup/Restore, Click on Browse.
2. A window will open, Go to the location where the downloaded template is, select it and click on Open
3. After clicking on open, Click on Upload and then your template has been uploaded and installed.