From the Analysis tab open the Analysis Factors dialog.  The Analysis Factors will default to the Distribution tab. The calculated distribution factors will appear on the screen. 

You can select the Computed option to allow the program to calculate the factors or select the Manual option to have the program use customized or user-defined factors. For customized or user-defined factors, you must select the specific span and beam and then check the Manual option and overwrite the calculated values in the text boxes.