As far as I'm aware, you can't. Most of Boss International assets have been acquired by Autodesk (see link below). DAMBRK has been on the way out for a long time and has been unsupported for years.
The Georgia Safe Dams program is aware of this and is aware of the need to move to accepting HEC-RAS breach models. My advice, contact the Safe Dams Office and ask for permission to submit HEC-RAS models. Or, subcontract to a consultant that already has BOSS DAMBRK in their pocket. You'll need an engineer of record anyway for any submissions to Safe Dams.