You can record your screen on a MacBook using the built-in recorder, which is pulled up with: Shift + command + 5
Now you can choose how you would like to record your screen.
To record the full screen, select the option labelled "Record Entire Screen".

Alternatively, select the option labelled "Record Selected Portion" to only record a specific portion of the screen.

Then press record, and the screen capture will begin.
To end the recording, press the stop button icon at the top of the screen:

Now the recording will be saved to whichever location is set in the options, which is the Desktop by default.