Initial XG 106 Setup on a Modem without a static IP

Hi everyone, I am a novice when it comes to networking so I apologize if this comes off pretty amateur. I have a client with an existing Dynamic Modem. I called the ISP and he said it is a dynamic IP but port 1 is bridged. I am bringing the XG 106 on-site to deploy this afternoon, initial config is done, I just don't know what to do for the WAN settings.

My question is what do I set my XG WAN to so that the XG can act as the sole DHCP for the network?

Here are the details below:

Current Modem settings provided by the ISP:

IP: 207.47.188.59
Mask: 255.255.255.0
Gateway: 207.47.188.59

DNS1: 142.165.21.5
DNS2: 142.165.200.5

DHCP = 172.16.1.0

Current users IP config settings:

IP: 172.16.1.40
Mask: 255.255.255.0
Gateway: 172.16.1.254

DNS1: 208.67.222.222
DNS2: 208.67.220.220

Thank you in advance!