You need to write the grad sec of ur dept. its best you send a statement of purpose highlighting your interests and attach all your results. I had to wait for months to get prescreened and then i was told to apply which i proceeded in doing as instructed by the dept. i filled and submitted in 1 day and I ensured my original transcripts was sent by the uni i did my undergrad to usask. My referres also referenced me in a weeek and my status was completed. Even online it showed i was prescreened/prequalified.