If when creating a payment method you need it to be associated to one of your bank accounts, e.g. Bank Account Deposit, you have to create the payment method by following these steps:
Settings > Basic Settings > Data List > New > Set a new > Set a new payment method.Settings > Basic settings > Data list > New > Set a name, e.g. Bank account deposit > Click on "associated to bank account" > Save.
This way when you make a purchase and/or sale document and in payment method you select "deposit in bank account" it will give you the option below to choose one of your bank accounts registered in the software or the one you have set by default.