It may take up to 1 hour until the app updates with your new videos. Also please load the demo again so that no content is pulled from the cache.
For Vimeo please also note:
You need to have an Vimeo Pro account: if you have a basic Vimeo account, then your videos will not be played in the app (this is a restriction by Vimeo).
You need to generate an Access Token in Vimeo Developer and enter this Access Token in your Contents settings.