Once you reply you will get a letter from them again after a gap of two to three months for submission of all documents along with a fresh IMM0008 (not simplified) and Schedule 1 and schedule 3 with supporting documents as given in the check list, with a time line of four months to submit them. After receiving them they will check if you have submitted them or not only on the expriy of that time line of four months. Then you are moved into the next queue of applicants in the Under Processing category. After that it is depending upon the accuracy and validity including PCC, you will be given a date for interview if needed (mostly yes). But more the accuracy and convincing the documents less the chances you will be required or grilled in the interview. Once you are through with the interview you should get the medical examination documents for undertaking the medical check with designated doctors listed on CIC website. Then you have to submit the medical to the Embassy along with your passport and visa approval letter for the visa to be endorsed on your passport. Remember the Visa will be valid only one year from the medical report and hence do not sleep over once the medical is done. Once the visa is stamped Please go to the CIC website and download the booklet before arriving and go as per the instructions given in there.
I think you will get more from this post on Bufflao
http://www.canadavisa.com/canada-immigration-discussion-board/recent-unread-topics/-t7085.0.html;topicseen
For Bufflao cases, Medical reports need to be send to Ottawa directly by DMP. Visa office will send VISA letter to applicant after all clearance from Security, Medical Office and etc..... VISA stamping letter is most advance stage of immigration as landing to Canada is final stage of immigration. Thank you and all the best