Let's find out if we can find the correct URL for a RTSP stream first.
Per page 57 of the manual, RTSP must be enabled. Refer to the attached PDF file below (page 57) and perform that enable of the RTSP stream in the NVR.
Download and install VLC media player from videolan.org
Open VLC, go to "media", then "open network stream" and for camera #1, enter URL of rtsp:/192.168.2.9:554/ch01/0 and click on "play".
You will likely be asked to enter the NVR's username and password; if so, enter those and click on "OK" or hit <enter>
NOTE: enter 2 "/" after "rstp:"; forum software does not allow 2 consecutively.
Or try this; change ONLY those items in the red boxes, then check before clicking on "OK".
If it works, repeat for each cam and change only the "Camera" number from the drop-down and then save that with "OK".
Do that for all cams 1 through 3.