Copy and Extract it into the Mods folder of where Civ 6 is installed on your system.
On Windows, it should be “…\Documents\My Games\Sid Meier’s Civilization VI\Mods”
Restart Civ
Go to Additional Content->Mods menu, and disable newly installed BBG to not conflict with real-time or other games
I did all of that and it didn’t work. I will point out that the save version is am getting has BBG version 5.2.9, and after your steps I have version 5.3, 5.1.8, and the static version. I currently only have the static version enabled in additional content.
You’ll need to download and unzip BBG5.2 from the Dropbox that adi linked. I just dropped it into my mods folder and restarted Civ 6. Worked like a charm.