1. Navigate to Blogger Dashboard.
2. Click on your Blog Title.
3. Jump to Layout tab from left pane.
4. Here you will able to see all your elements on your layout. Click on an Add a Gadget link.
6. Now you can sum up a title on Title field if you want and add your third-party content or code right into the Content text field.
7. After adding your code, click Save button.
8. Now arrange or position your element by dragging it over the layout.
9. Preview your blog for added element on your blog.
10. Once confirmed preview, click Save arrangement button on top.