I recommend you watch my previous video on editing first: https://www.youtube.com/watch?v=6xS8LykRUj0
Working through each scene of your novel (I recommend using an outline to do this) is a great early step in the editing process. It can help you to grasp the necessary large-scale changes and it can help pinpoint where you need to brainstorm new ideas. As always, start with the big picture and then work your way to smaller details.