I made sample video couple of days ago. I used cheap tablet" Wacom" https://www.amazon.com/Wacom-CTL490DW-Intuos-Creative-Tablet/dp/B01N8XUMJI/ref=sr_1_9?keywords=wacom+intuos&qid=1563037291&s=electronics&sr=1-9 It went well. You will need to adjust the tablet dimension to the place you write in on the screen. I use smart draw and also SketchBook, both free. I use Camtasia for recording, it is very nice and equiped with Camtasia Studio for editing with is easy and great for this purpose. I think You can get it with discount if you are a udemy teacher (used to be like that, not sure how it goes now) Here are also some videos to help you handle the tablet/screen setup and don't get siappointed, it takes sometime to get used to it and do it freehand. https://www.youtube.com/watch?v=a5Kqpnx8fvw https://www.youtube.com/watch?v=jOsCstC5F9o
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