This is the main window of Shell and Tube Heat Exchanger Design where you can set the Calculation mode, the Units of Measurement and Database information conerning the software and the user 

In the Shell and Tube Components database you may enter and modify information about the Units, Rating Mode or Design Mode 

This is the Design window where you can follow 10 steps. The first one asks you to enter Shell side data and Tube side data, for which you must specify the Temperature, Flow rate and main temperature