To Add DBA Details to a Business Entity/Company:
From the Business Entity/Company Snapshot, click on the View More Details link.
Under Qualifications & Licenses section, Click Doing Business As (DBA).
Click New DBA.
Enter all mandatory fields, and any other fields required by your organization, and click Save.
The newly added DBA displays.
Also see article:
SuperAdmin Templates | GEMS Help Center - Entity DBA Import section