A 5.1 speaker system is the standard surround sound setup for home cinema. A 7.2 surround sound receiver would therefore have two subwoofer outputs.
An Atmos system starts with a conventional 5.1 or 7.1 surround sound speaker setup. Then you add two or four speakers to project sound that rains down from.
Learn how to set up your speakers for 7.1 surround sound. To experience your system at its best, you might need to fine-tune your setup after some initial.