Change blog template using available template outside of blog
To change your blog template, you need to log in to you blogger account using your Gmail account.
i) On the same page, just beside the "Go To Post List" option, click the down arrow "More options", as shown in the picture below.
ii) Click on the "Edit HTML" option .Below the preview image towards the upper-left part of the page click "Proceed" in the next window that appears. This will enable you to edit your HTML code directly.
iii) It is best that you copy the original code and back it up before you can move to the next step. You may then paste in your HTML code from an external source. Ensure that the code is correct and lacks no errors.
iv) Before you save the changes you may preview your blog to see if the code works. You may then save the changes if the code works.