Code for what page?
The code above can be found in the file mentioned blog-right.php
If you are using a child theme for this, you would copy that file and place it in the child theme’s folder where the style.css is for it. Then make your edits to the code of the page file as described above. Of course, you may want to read more about child themes before doing it, otherwise if you do this without the child theme, simply open the file blog-right.php and make those couple of edits.