Appearantly, the option to Defer Upgrades option in Settings > Update & Recovery establishes the CBB branch for you if you have Pro or an education edition (not sure about the edu edition though)
See:
What Does "Defer Upgrades" in Windows 10 Mean?
This makes more sense than what some members have said that
Windows 10 production will have rings like the Insider program. While technically it might be the same thing, using the terminology from the Insider Program to describe operations associated with production code obfuscates the difference between the two (Insider=development code, possibly very buggy ... Retail = production code thoroughly test, but still contains nuisance bugs)
Yes, we'll know on or about 29 July.
And then MS will change it all again in the Redstone releases next year