This part of the GUI let us inform the type of design variables: Integer or Real and their bounds. The order in which the design variables are informed is important, because that is the order in which they are passed to the analyzer. Buttons Add, Delete and Edit let modify one design variable at a time. Buttons Move Up and Move Down let change the order of appearance the design variables. The Design Variable Identifier is just informative and is used only within the GUI and the optimization project.
In figure 3 it can be seen the window that appears when you hit the add or edit button. As can be seen, there you can choose the type of design variable (integer or real), assign a identifier to it and its bounds.