New Tutorial: How to Use the New YouTube Channels

YouTube just rolled out a re-design of their channel pages. It's radically different from the old channel design, so the recent site wide roll out has generated a lot of usage questions.
I've been using the "beta" for almost a year and thought I'd scratch up a little tutorial on them now they they have rolled out to everyone.
Most everything on the new channel design can be changed without leaving the channel now. No need to go to different places around in your account settings to change various aspects of the channel like you did with the old design.