Not all cameras have this feature. It needs to have the same private protocol as the NVR, such as my POE camera. https://www.aliexpress.com/item/1005009302185001.html
1)Update the NVR software version to the latest. Home -> Alarm -> Face.
2)Enable -> Record Channel -> OK
3)Click the right mouse button – > Face
4)Select the date (1), click Play (2), and select a different length of time, which can zoom in/out of the progress bar (3); the purple progress bar is a face alarm (4); select the next/previous alarm event (5).