Blogger template consists of two type templates; Classic Template and New Blogger Template. It's there a difference to install both templates. But are not difficult to install them respectively

Classic Template :

I think this type is create in html basically. The script of template structure write or form in "txt" file format. See the complete tutorial to change blogger classic template here

New Blogger Template :

This one type developed "css" and "javascript". The script of this template usual is "xml" file format. Nevertheless, You just need to download a file template whatever you like from anywhere provide them. Next you just upload it and your template will be change outomatically.
To change to the new template, sign into Blogger Dashboard, and in the list of blogs, click LAYOUT in the section for the relevant blog, then click the EDIT HTML sub-tab. This will open the template editor and at the top of the template editor, you will see "BROWSE". Click on that, then open the xml file that you have just downloaded, then click UPLOAD.

Relate Link :

• Modify the New Blogger Template LINK
• Basic CSS Selector LINK
• To witch old template to another provided by Blogger LINK