It is very simple, you just have to know that, out of the box, the AP accepts only http connections from clients in its subnet. Once you reach the web management page, you can reconfigure the device...

I'm trying to install a new EAP673 (aka EAP670 V2). I managed to give the device an IP address with my dhcp server. I can ping the device, but cannot connect on tcp ports 80 or 443. A capture showed...