1. Open the app you want to record. 

2. Press the Windows key + G at the same time to open the Game Bar dialog.

3. Check the "Yes, this is a game" checkbox to load the Game Bar. 

4. Click on the Start Recording button (or Win + Alt + R) to begin capturing video.

5. Stop the recording by clicking on the red recording bar that will be on the top right of the program window. (If it disappears on you, press Win + G again to bring the Game Bar back.)