As we mentioned this morning, Windows Insider has undergone significant changes to its development, with a simple renaming of the rings. The Fast ring became the Dev channel, while the Slow ring is now called the Beta channel.
More specifically, only users who were in the Slow ring and from today Beta channel will be able to download this version simply because Microsoft does not intend to include significant new features. Instead developers have focused only on improvements.
The Fast ring or Dev channel as it is now called, will be used to test new features that will not have a release date. Most likely some of these features that will be included in these distributions for Insiders, we may never see them in the Beta channel, or we may see them later.
The first edition 20H2 of Windows 10 is 19042.330, but instead of being automatically forwarded to users who are subscribed to the Beta channel, Microsoft only makes it available to those who manually check for updates. So to download the new beta build, follow the path:
Settings - Update & Security - Windows Update - Check for updates
Once the new version appears on your device, you can download and install it.