Add at least one merchant account. 

Note: If you use multiple Blackbaud programs, you add the merchant account to the Blackbaud Payment Service through only one of those programs.  For example, if you use both Blackbaud NetCommunity and The Raiser's Edge 7, when you add the merchant account through one program or through BBMS, it automatically appears as an available merchant account in the other program.  

Please also see
How to add merchant account