I feel stupid but I can't figure out how to link to a playlist that auto-plays the videos, without linking to a specific video. There has to be a way 
In my endcard I have a "latest videos" annotation that links to a playlist of all videos (reverse order), so the "first" video changes every week. So every time I upload a new video I have to go in and change the annotation links on ALL previous videos. As you can see, it's a growing problem.
Any help is much appreciated.

In my endcard I have a "latest videos" annotation that links to a playlist of all videos (reverse order), so the "first" video changes every week. So every time I upload a new video I have to go in and change the annotation links on ALL previous videos. As you can see, it's a growing problem.

Any help is much appreciated.