The process is pretty easy and works for all Mac (Pro or Air), the steps are listed below
1. Open your Mac and press f4.
2. Click on Quick time player, now it will be shown on your menu.
3. Now press control and click on that quick time player again.
4. Now click on new screen recording and click on the red dot.
Now you can either record full screen or limit to a particular part of your screen.
5. Once you are done, again press control and click on the quick time player, click on stop screen recording.
Now you can see your video, you can share it or just save it to use later 🙂