Search and Select your customer in the CLIENTS - Client List menu.
In the details screen of your customer, under the tab Coda, you can add a bank account by clicking New Coda
In the next screen, enter the bank account(s) you want to add
This screen also contains the list Non-orderable bank accounts: accounts that have already been requested, which are therefore being processed for this customer and can no longer be ordered.
Once you have made your selection or added , click on Save Mandate.