Published on Brock University (http://brocku.ca)
What Turnitin.com Does
Instructors: Getting Started
Contact TurnItIn@brocku.ca  to obtain an instructor account.
Turnitin.com  has all the up-to-date information you need to create your account and administer assignments. If you are looking for someplace to start try the 'New To Turnitin?' button.
Instructors should make it clear that they intend to use Turnitin, for example in the course outline and in the description of assignments. Students should be given the option of not submitting to Turnitin. Brock University requires that students be given the option to declare that they do not want to use turnitin in advance and submit revisions or drafts of their work in advance of the due date (or other similar accommodation). As per the faculty handbook, students with a principled objection must be offered an alternative: http://www.brocku.ca/university-secretariat/facultyhandbook/section3#_genIndex63 
This video describes the basic set-up of a course for instructors that already have an account with Turnitin.com.
Go to turnitin.com , create your account based on the information provided on the web site and add your course based on the Course ID and password your instructor has given you already.
Turnitin also has a guide for students about how to submit a paper  and provides this video:
Results and Reports
More about Academic Integrity
Individuals interested in Turnitin.com may also be interested in Brock University's Academic Integrity website .