Manual Payments button works but how do I apply/approve payment when it's paid

In the Events + Plugin there is an Extra/Addon for Manual Payments.

I have been able to get this to work, however...

The Manual Payments button works and says that payment has been paid after I click the Made Payment Offline button but how do I apply/approve payment when it's arrives into the bank account?

Event Page:

Click I'm Attending
Click Login with RideAdv
Register with the site and click Submit
Click the Manual Payment button
Click I Have Paid Offline
The Thank you for your payment message appears

All good... now whe we verify that the payment has been made and is in the bank account, how do we acknowledge to the Event Attendee and our records that it has been paid?