Help with bought theme for Blogger

Hi, I am really new to all of this as a graphic designer and am really struggling editing this this theme in html. First off, the owner did give instructions and a “how to”, however, I cannot access some of the widgets as some of the blocks are covering other blocks and one cannot drag and drop or move these elements.

Is someone able to advise me in maybe how to “extend” my window so that I can view everything and edit accordingly? Thanks very much!

Screenshot below: