To enable Turnitin on an assignment, start by clicking on the "Course Admin" tab in the blue course navbar.

Scroll down and click on "Assignments" under the Assessment section.

Find the assignment and then click on the caret to the right of its name, then click on "Edit Assignment"

Click on the "Evaluation & Feedback" tab on the right side of the page.

Scroll down to the bottom of the tab and click on "Manage Turnitin"

Check the "Enable Similarity Report for this Folder" box. You're also able to check the box that allows students to see the report of their submission.

Click on the blue "Save" button when finished.