That is correct. Depending on what NVR you're using it has either 1 or 2 LAN ports, always use #1 to go to the router. Plug it into the L:AN side of your router. LAN side of router is generally 4-5 ports grouped together, then the WAN side (goes to modem) will be by itself usually, and can be left empty in your case.
You do not need to turn DHCP off in the router.
Yes for them to work reliably on Wi-Fi, "wireless" needs to be set for the default.