The BEEP base 390mm wide and 480mm long. Any hive with a maximum width of 480mm can be placed directly on top of the BEEP base. Regular size hives fit perfectly on the BEEP base.
It could be that you have a hive that is too large for the BEEP base, e.g. shortest side is larger than 480mm. You can attach a self-built wooden board to the scale with four screws and the supplied metal clamps. Place your hive on top of the frame to start using the BEEP base. If you have any questions on how to do that, please reach out.