Brand Registry is often dependent having a filed for and received an active trademark, which can take a varying amount of time - months, typically.
However there is a bit of a shortcut available :)
Note, this seems to not work with Amazon's IP accelerator, so skip that.
The steps are simple and our clients as well as those in various groups are reporting similar results - having been accepted into Brand Registry in a matter of days to a week or so.
1. Apply for a trademark. If going direct, you can find the USPTO link at https://www.uspto.gov/trademarks-application-process/filing-online
2. You'll receive a trademark application number. Save that.
4. Submit the application with your trademark application number