First, you need a smartphone, such as iPhone or Android. Then you need something to hold it over your notes, such as this. Then you need diffuse lighting at or above the level of your smartphone, one illuminating the left side of your notes, the other the right side of your notes. If your lighting is very diffuse, then shadows should not be a problem as you write from one side of the page to another. These work lights might do the trick. You'll have to figure out how you want to suspend them, however.
Finally, you need video editing software that lets you trim your video so your beginnings and endings are crisp and where you want them to be. You can download a free version of DaVinci Resolve that works on Mac and Windows platforms and can output FullHD (but not UHD) video. You can use the microphone built into your phone.