WINFAP-FEH 3 required you to modify which directory to select Peak Flow Dataset gauging stations from depending on the type of analysis.
This is not required for WINFAP 4 and subsequent versions. Within WINFAP (4+) simply select the top folder for the Peak Flow Dataset that you wish to use in your analysis. The organisation of folders is not important as WINFAP will use all files within the folder/sub-folders and assess suitability for pooling and/or QMED independently.
In WINFAP 5 you should select the top folder which contains the manifest.xml file.