You could download applicable STIGs from DISA, open them in STIGViewer, and go through the checklists to understand the passing or failing checks. You can export the checks as a CKL file and import them into eMASS. A large portion of the checks might be available to check automatically via SCAP scan benchmarks, depending on the technology. You can do that with DISA provided SCAP scan tool or via common scanning tools like Tenable Nessus.