The page you’re referring to in your second screenshot is only available if there are system generated reminders pending (enabled through Credit Control Settings).
You can view a list of outstanding invoices by either clicking on Money owed to me on the dashboard, or by going to Sales >> Outstanding Invoices. There are numerous other reports which help, as you’ve discovered from the other forum posts - Creditors / Debtors report and the aging reports.
Was there anything you were looking to do in particular, or was it just wanting to see what reminders were pending?