Explaining the Photon AP Provisioning Process

I want to understand how the AP provisioning works on the Photon. It seems that the universally accepted method of provisioning an IoT device is for the device to act as an AP then the user connects to it in order to send the Wifi AP credentials over via smartphone. I’m assuming this could be done via UDP or TCP.

I might be wrong but the device can’t act as a AP and a Station at the same time. Correct? Going off that theory, how does the device know that the Wifi credentials are correct? It must have to shut down the AP that it creates to try and connect to the user’s Wifi, right? If the credentials are NOT correct, how does it let the user know on the smartphone side? At this point, the device’s AP doesn’t exists and the user would have to jump back on it again. This doesn’t seem to be happening when I try to provisioning my Photon through the Tinker app. What’s really happening there? Thanks!

TL;DR Explain the Photon Wifi provisioning process to me like I’m 5.

Does anyone have any thoughts on this process?