The Program Order dialog also establishes computation order and data flow for forecasting. In addition, the Program Order dialog provides the mechanism for defining supplemental programs, adding the supplemental programs to the program order, and establishing data flow for supplemental programs. To access the Program Order dialog, click on the Setup tab and select Program Order from the Models menu. 
Program Order Dialog

CWMS generates a default program order that contains HEC software applications. By default, the program order for a watershed is: MetVue, HMS, ResSim, RAS, and FIA. If you change the order of programs after a forecast run has been configured, you may disrupt the orderly flow of data and invalidate any existing work.