I have been trying several times to configure the embedded WiFi as Access Point: the client connects but a default IP is assigned and it cannot access internet.
Because the specs state that camera also has an Ethernet port, I'd say the AP mode allows a smart phone or wireless laptop/PC to more easily connect to it for configuring.
AP mode, called "ad hoc" for many years, does not look for a gateway / Internet IP. To place on your local Wi-Fi, you would likely disable "AP mode" (putting it into what used to be called "Infrastructure mode") , have it "scan" or "survey" for your local Wi-Fi access point's SSID, input password and "save"; it is likely set to DHCP and will receive an IP from your router.
It's also likely that if you plug into the cam with an Ethernet cable connected to your router's LAN port you can configure that way.
BTW, it's best that a cam does NOT have direct access to the Internet!