Given dimensions, strength class of the concrete section and the steel grade of longitudinal bars you can require to the program a first design of longitudinal bars for selecting in "Section Data" Tab dialog window the option "Bending reinforcement design". For a general section such dialog appears as below:
Diameters of bars (longitudinal and for stirrups) used in design are those stored in Materials Library (that you can modify as you want).
Longitudinal bars provided by the program after the first run ("Checks" Tab selection) are uniformly distributed along the perimeter of the concrete regions. After running the check you can easily modify their position and diameter and run again the checks.
After the design of then bending longitudinal bars you may define hoops (up to 10) and cross-ties (up to 80) as indicated in previous paragraphs or in the Stirrups-Ductility Tab window.
Selecting Checks Tab the program performs new checks for the modified stirrups. And so on interactively. Printing results in Check Tab windows is possible to evaluate in detail eventual non conformity of checks.