When the Select Sections form appears, select any frame section from the list. This assigns the new section property to the selected beam, thereby changing the Current Design /Next Analysis section property. Note that if an auto select list is assigned to the beam, using the Sections button sets the auto select list assignment to NONE.
Access the Select Sections form as follows:
Select the Analyze menu > Run Analysis command to analyze the model.
Select the Design menu > {Composite Beam, Steel Joist} Design > Start Design/Check command.
Right click on a beam while the design results are displayed to enter the interactive design mode and interactively design the beam using the Interactive Composite Beam Design and Review form or the Interactive Design form. If results are not currently displayed, click the Design menu > Composite Beam Design > Interactive Design command to enter the interactive design mode and access the Interactive Composite Beam Design and Review form or the Design menu > Steel Joist Design > Interactive Design command to enter the interactive design mode and access the Interactive Design form.
Click the Sections button.