How to go about making educational videos of handwritten instructions on a digital pad, where the hands won't be included in the videos? How do we use a digital board/pad to make pre-recorded (not live) YouTube videos of the handwritten instructions, so that hand(s) wouldn't be visible in the videos, but you'll actually use your hand (and not the computer mouse) to write on the board? So basically, to make these videos, you'll write on a digital pad/board connected to your computer, so the computer screen would contain just what you're writing minus your hand, and the video of those writings can be saved afterwards? The best descripotion is some Khan Academy videos: e.g. 
                
             is where you see just what you need, minus the hands, or the instructor himself.

If possible, how exactly do we do it? One idea is described here - 
                
            , but I'd still love to see if there're other simpler ideas out there, possibly not involving buying a very expensive digital board. Some digital board are less than 100€, but some are 1000€ (!).
The easiest way to do this would be to get a graphic tablet (like a Wacom tablet or a cheaper alternative) and record the screen as you write on a drawing program such as gimp, illustrator, Photoshop, paint.net, etc. with a recording program such as OBS. You can set up custom pens that use the speed, angle, pressure, etc. of your drawing to imitate the look of a pen and to create a similar effect to one of these videos.