I want to know after I run the analysis for steel design code check I got these sections in the analysis window in the picture showing steel sections with a questions mark. what it is mean? I only used the first two sections in the structure.
Seems like you have asked for member selection. These sections with the question marks are the ones which the software has selected. The ones with tick marks are the ones you specified.
Is there an easy way to assign the sections for all the members that the software has selected for the design? there is more than 4000 elements need to change their property sections!
You can use Update Properties button the Postprocessing workflow.