Usually, A monitor is necessary to get serial number of system so that you can use this infomation to add system on phone app.
But phone can obtain system's serial number by itself without a monitor. Below are instructions.
1. Connect DVR to router by an ethenet cable so that DVR accesses Internet.
2. Search xmeye in Apple store or Google play store.
iPhone&iPad APP (xmeye) https://itunes.apple.com/cn/app/xmeye/id884006786 mt=8
3. Make sure your phone is using wifi from the router and the router is connected to DVR by ethernet cable. In other words, DVR and phone are connected to same router and in same network area.
4. Run App xmeye and click register user.
Create a user name and password by your email and use that account to cloud login.
5. Click plus icon at top right and click search to detect DVR's serial number.
6. It will detect system's serial number. Click OK to add system.
7. Tap device on the list and choose one camera to see live video.