Once you ftped the file to the ns/service, basically your service input should be ffdata(object stream),so in your flow use streamTobytes,bytesToString(flatfile content) further down use WmFlatFile Adapter and create FFSchema (for .csv data) and parse with wm.flatfile:convertToValues …continue with your mapping what ever your flow says.
And yes getTransportInfo service will just give the protocol information,contenttype,filename information in the pipeline.
HTH,
RMG
#webMethods#Integration-Server-and-ESB#webmethods-Protocol-and-Transport