viewneo automatically updates your content every 15 minutes. If you want your changes to be displayed instantly, go to the player menu. (How to get to the player menu can be found here.)
Once in the player menu, you can go to the page titled "System". Once there you will see a log window. By opening this window you will be able to follow the automatic and manual download progress. Start the update of your playlist by clicking "Update". When the content is done downloading, the new playlist will be played after you leave the player menu.