To start a design, select single / multiple pump, direction of rotation and speed. Click on "first pump stage" and select one of the pumps listed. For multiple pumps, click on "Add stage X if required" and select the next pump. Enter the required operating pressures in the calculation table and click on "recalculate". Next to this button you will find an indication of the total output required. For multiple pumps, enter the pressures that are required at the same time for the highest total output. When all pump stages have been entered and you need a bellhousing, click on "Add bellhousing øXXX.