Blogger or a.k.a blogspot is one awesome blogging platform and you're thinking of making a backup of it is a wise idea to save your blogspot blog.
Blogger is free and that is what making it attractive and there is no limit to it as long as you follow their blogger content policy and as your blogging grow soon there will be coming unexpected calamity and all your hardworking will come to an end if you don't make a backup of your blog as early as possible.
Did you know that every month a lot of blogs get hacked, templates get ruined and etc. and having a backup takes a way a lot of pain out of the recovery process when things goes wrong.
When backing up your blogger blog, you will want to backup both of your templates and your content, like your posts,pages and widgets so that you can save your blogspot blog if something goes horribly wrong with your blog. Here's a short video how to backup your blogger blogspot blog.
This video is not my own. Credits to the owner. This video is for demonstration purposes only. Enjoy watching!