Lock icon could be misleading/confusing on the preview post

When I was creating a post, I wasn’t sure what the lock icon did, so I thought that was the Save feature for that specific post, so I hit the lock icon to lock the post, and I refreshed the page and my post was erased. It wasn’t until later that I saw the Submit button on the far bottom right.

I think it might be helpful to both have the Submit button in a more obvious area (especially since the Submit button is right below the arrow icon for the post generation, so it’s a little busy) AND it would be helpful to specify what that lock icon actually does. Maybe a tooltip when hovering over the lock or a fading UI text when locking and unlocking?