Do I send my documents (including the official transcripts, reference letters, statement of purpose and vitae/resume), to the graduate school or the department directly?

No. Please upload all of your documentation (including the official transcripts, reference letters, statement of purpose and vitae/resume) through the Prospective Student Portal.  The Graduate School will refer applications and the respective documents to the program only when application is complete.  If the application packet is incomplete the department will not receive the application packet.  The department can only make a decision once we receive a complete application from the Graduate School.