If you are converting a generic wifi IP camera to ethernet, it may not be that simple as many are default hard coded to a static IP of 192.168.1.168 and login info admin/admin.
From there you can login to the camera and assign it to DHCP by going to http://192.168.1.168
For security these cameras + DVR should be on a separate untagged VLAN or if possible a physically isolated non-internet connected switch/network.
The reference below is applicable to many of the random generic IP cameras from China.
Reference: https://www.herospeed.net/en/ver//Manual/IPC/IP%20Camera%20Quick%20Start%20Guide%20CK.pdf
If the above doesn't work and you don't know the IP. you can always use tcpdump or wireshark to figure out the IP address of the camera.