I don't know if this has been posted before but I stumbled on it on YouTube yesterday:
https://www.youtube.com/watch?v=xyC6AU3EiCQ
It's a guide to building with hand tools the kind of jig you need for mitering the corners of boxes or other longish edges. It is also, in my opinion, an absolute model of clarity of explanation and demonstration and so is much better than many of the wobbly camera presentations you get on YouTube.
https://www.youtube.com/watch?v=xyC6AU3EiCQ
It's a guide to building with hand tools the kind of jig you need for mitering the corners of boxes or other longish edges. It is also, in my opinion, an absolute model of clarity of explanation and demonstration and so is much better than many of the wobbly camera presentations you get on YouTube.