the last index is length of list your list
When the video ends, the next will start
This action has been done
But at the last video, a problem appears because there is nothing after it
I think everything is correct but it does not work
not really… you have to learn how to work asynchronously…
after the first video has been played, then start the next, etc.
see that logic in this example App Inventor Tutorials and Examples: Webprefetch File by File | Pura Vida Apps (it is something completely different, but the asynchronous logic is the same you have to use in your project)