When it comes to appointing us to act as your tax or BAS agent for another entity (other than yourself) then we need you to do a nomination to the ATO first. Only authorised contacts can add the nomination and you can find detailed instructions on the ATO website here: https://www.ato.gov.au/agentnomination.
You can also download a pdf version with the step-by-step instructions here: How to Nominate an Agent in ATO Online Services for Business