this is also a feasible option.
however, as the first step I would verify if you can use some standard report, as this requires almost no or very limited efforts (e.g. just to modify layout) - you can find dozen of the standard ones under under Treasury and Risk Management -> Transaction Manager -> Information -> System Reports.
of course, in case your reporting needs cannot be met by the method mentioned above then you should consider using logical databases of Transaction manager - in your case I would assume FTI_TR_CASH_FLOWS is relevant. In combination with the SAP queries, they are simple and powerful tools for creating reports that particularly meet your specific requirements.
Kind regards,
Renatas