I recently applied for a postdoctoral fellowship that worked similarly. It was confusing to me at first also. There was no "submit" button to send in the application once and for all. You just input your formation and it will get seen by whoever logs in as a reviewer.
The "deadline" to apply was 11/1, which meant you must register in the system by 11/1. But the application data was still editable, even after the deadline. I was told the review of applications won't start until 11/8, so any changes made before then would definitely be seen by anyone on the committee who reads the form. The data is still editable now, even though the review process is finished.