I'm literally running out of things to write tutorials on. If you have something unique to ask and you think it will be a great tutorial material, please feed me your ideas by posting your questions here. Now back to this post. This time it's for beginners.
Third party templates are templates that don't come 'built-in' in Blogger's layout. It's created by some third party. And most of the time, it'll be hard to tweak/modify these templates. BUT, most third party templates clearly beat Blogger's 'built-in' templates when it comes to cosmetics. And it's not all difficult to add one to your site.