ITS 6 upload. DSC/penalty related query

I am working in a company establish in feb 18.and joined last month only I am going to file income tax return ITR6. which was due on sep 18.
I am getting error on dsc non availability . I downloaded utility from IT site and open JAR file but don't know what do do next.
I don't have any digital certificate with me. do I need my director Digital key ?
also want to know penalty amount for non filling return timely. how to pay the penalty.
I am new to income tax and Tds.