You can use Backstage to update VEVO channels that have had at least one video delivered to them.
To update a channel first go to the channel section in the right-hand menu via YouTube<Channels
Search for the channel you wish to update
Click into the channel
You can now update any of the following fields -
Avatar -Hit upload to change the image
Banner-Hit upload to change the image
Keywords - Must be added in a comma-separated list with a 1000 character limit
Description -1000 character limit
Made for Kids flag -Tick the tick box to flag a channel as made for kids
Channel trailer -Can be searched for by Title, Artist ISRC or Youtube URL
Once this is selected you will see the thumbnail of the video, artist, and video title above the trailer name
Once you have made all your updates hit publish on the top right-hand side
You will then see this "Publish Queued!" message which shows this has been successfully sent to YouTube.