If you want to operate the DAB112OR with batteries, it is important to note that they are rechargeable batteries. To charge the battery, you can use the supplied USB-C cable, which you can connect to a 5V adapter. If you don't have one, I have found a compatible one for you: https://www.galaxus.ch/de/s1/product/gembird-chargeur-secteur-1x-usb-c-1x-usb-a-12w-noir-12-w-usb-ladegeraet-47848248.

The following link will take you to the operating instructions: https://www.soundmaster.de/downloads/Manuals/BDA_DAB112OR_21544.pdf