Sorry
@Avocado had to edit the link. Can't post those here.
As far as how shorts work, here are the rules:
1. The video
must be less than 60 seconds.
2. The video
should be in vertical format. This is not a requirement... but they perform better if its vert.
3. It
should include #Shorts in the Title or Description. This is also not a requirement, but it does help YouTube to find Shorts videos and put them on the Shorts shelf for discovery.
The algorithm they use is obviously real similar to Tik Tok and Reels, they just want to plaster content out there so discovery is a little different. While the numbers are going to be really weird compared to regular videos the same basic principles apply; watchtime and CTR are the metrics by which success is determined. The one catch is that while you can and should apply custom thumbnails, SEO etc (for discovery purposes outside the Shelf) YouTube gets to pick a screen-grab for your thumbnail on the Short Shelf. You can't affect that and it is total luck of the draw.