If you're ready to tinker - here is how to get the more features working right now

[daniel]

As other have posted, the process doesn't work for me.

First problem is that I see two of each channel including two 'development' channels.  I have tried both.

Second problem, I switch to 'Development', and nothing happens.  Stays on 'Channel Settings' card.  After waiting a few minutes, still nothing.  Sometimes, the Settings app freezes here.  Other times, I can go back to previous settings card.  Either way, Settings always shows 'Stable'. 

Third, switching between WiFi only and 'Any' update and rebooting a few times seems to have gotten the process started.  I had to go back to Updates screen to see it downloading.

This may be just a lack of any informational message in the UI to say something like "New update downloading now" or something to that effect.

Just a quick edit to say I hope like I don't sound like I'm complaining.  Thank you and team for all your hard work. I'm a QA person by profession, so I usually point out every issue.  Can't help it.

The same thing happened to me at the beginning.
I just kept switching to Development, and then suddenly worked.
Try to update everything even if from stable. That might help fix bugs, including being able to switch to dev.
Be sure wifi is connected. Maybe it can't download updates?