Question about Nanoleaf Aurora Rhythm

As Dennjs has already written, you cannot operate the Rhythm module alone. You need at least the Starter Set.

In principle, you can buy everything individually. However, it is advisable to start with a starter set. Because you will need a controller anyway. Then the panels and if you want the Aurora Rhythm. No matter where you start, you will need at least one of all 3 things that are necessary in the end. Controller/Panel/Aurora, so I would start with a starter set that is either without Auror or with Aurora. Depending on your budget :-)

They only work as an add-on to the panels and are plugged directly into one and automatically recognised.