Then connect all of your devices (PC’s) to the switch via ethernet cables.
You will need to configure NAT to work on the Ethernet interface connected to your Cable modem. You will also need to configure that interface to get it’s IP address via DHCP (Most likely…it is possible that you have a static IP, but doubtful).
On the interface that is connected to the switch, you will need to put a static IP. I would suggest the following:
You will also need to configure DHCP for that network.
You MAY need to configure a default gateway as well on the router, I don’t remember in this configuration if ZS will figure it out on it’s own or not. Either way, hopefully this will get you started. There are plenty of things on the internet to help out as well. Just know, that at a minimum, you will need DHCP, and NAT configured. You will also need a minimum of 2 ethernet interfaces on your ZS router.