Payment program Customizing steps(for the program RFFOUS_T )

Hello all, we are planing to generate ACH file for the Remitanace advice, when we run the payment program( F111 - to pay payment orders)

I dont know the required customizing that i need to do in FBZP, to get ACH file when we generate payments for a specific payment method(say ACH).

Could please some help me with the step by step approach to get ACH file from payment program.

Iam aware that i will generate from the program RFFOUS_T but i dont know the required customizing to get that.

any help will be greatly appreciated.

Thanks.