How do I load the AISC steel material properties so that I have the ability to assign them as material properties to my steel members in Staad Pro Connect v22?
Not sure whether I understand your query properly. If you want to add a new material to STAAD, you can always do that from Material page. Also there is a long list of custom materials which you can access and add in STAAD from Utilities > User Tools > Add material tab. Once included in the material list, you can assign that to any member.
If you want to permanently add a material to STAAD, you can add that directly in the StaadPro22.00.00.ini file located in "C:\Users\user.name\AppData\Local\Bentley\Engineering\STAAD.Pro CONNECT Edition\Default". Don't change anything else in this file, else STAAD will not work properly.
To add any custom section to standard database, you need to modify the relevant database file from SectionDatabaseManager. Don't forget to save the changes, else it will not be highlighted in the property table.