The camera is accessed via various applications. The simplest way to record a video is via QuickTime Player -- just go to File > New Movie Recording and select the built-in camera [see screenshot below]; then just point & shoot.
This Apple support page provides links to other application-specific instructions for using the camera -- just select your version of macOS up top..
Thanks for the information! How I can get that Quick time player on the top aside apple as you have on the screenshot? I have there Finder. I know how to get ( open ) Finder there, it's on the bottom. But where is the Quick time player? What it means quick? I need to record the thing hours. If I record with that camera, does the recording takes a memory and saves to the harddisc? How much memory an hour by camera will be used? Video included.
QuickTime Player comes with every Mac. Just open it up from the Dock and you'll see its menu up top.
Here's Apple's manual for it:
And here's the section on recording a movie [with the camera]:
Yes the movie will be recorded to your disk [just like audio] only the file will be much larger, depending on resolution -- High Quality [1280x720] or Maximum Quality [around 7x-8x bigger]. Do a short test recording and then extrapolate from that to determine exactly how large any recorded movie files will be -- then make sure you have enough free space on whatever hard disk you Save the recording to.
Open your Hard Disk in a Finder window and go to the [root-level] Applications folder -- you'll find QuickTime Player there. You can open it directly from there or drag it to the Dock for easy access in the future.