Every device connected to the router, including a computer, smartphone, DVR, NVR, IP camera, no matter by ethernet cable or by wifi, will be distributed an IP by the router.
All connected devices are listed in the router's page. Here is the method to find it.
1. Find your router's address. Usually, the router's address is the same as your computer's gateway.
2. Access router by its IP on your computer browser. The default user name and password of your router is on the label? of router.
Please notice router's user name and password is not the same as wifi's user name and password, you have to clarify them.
You can also search your router's default user name and password on google.
3. Find the DHCP list. Picture below is my router's page. Every router's page is different.
4. Finally, your computer can access DVR by its IP