I have an app approved for testing, it shows that I have been notified, but does not show in Test Flight. Completely unsure of what to do. ??

Hi, So I have just found out that once I submit my app, I can not edit images and video for the in store profile. I am wondering why as it seems a silly law. What if I added a new feature or a major character in a new update??Shaking head very much.