For the OpenFlows products, the user's manual (user guide) can be found in the root of the installation folder, in PDF form. It contains the same content as the in-program Help. For example, for WaterCAD, it will be located here:
"C:\Program Files (x86)\Bentley\WaterCAD\WaterCAD V8i User's Guide.pdf"
For the CONNECT Edition versions:
"C:\Program Files (x86)\Bentley\WaterCAD\WaterCAD User's Guide.pdf"
If you are a new user learning the software, you can find a wealth of other learning resources here: