When you automate your report, it essentially passes 3 stages: data gathering, review/comment and ready for sending, which is reflected on your report's status.
When report is in data gathering stage, you can still edit the stats and automation settings, when you hover over it and click on the three dots in the corner.
When the report is in review/comment mode, you can approve it for delivery by selecting 'comment' in the menu.
If you click on 'comment' it will take you to the view mode where the comments can be edited. Once you are done, you can click on 'done commenting':
After that you should be taken to your home screen, where report status should be changed to 'ready for sending':
After the report is sent, it enters the 'automation cycle' once again, starting at the data gathering stage.