GS724TPv2 Switch and DHCP

Good evening.

Newbie here.

My old switch died and I purchased a GS724TPv2 for a replacement.  I figured that I'd upgrade to something nicer but now I've gotten myself into a problem.

Previously, I used the Xfinity modem to provide Internet, our wireless network and DHCP for the devices plugged into the switch.  Devices on both the wireless and wired network could see each other.

I put the new switch in place and realized that it, too, had a DHCP server. I know you don't want to have two DHCP servers runing like this, as now the wired and wireless devices can't see each other.

What I don't know is how to fix this.  Do I just disable the DHCP server on the modem?

Super lost.  Thanks