...
Navigate to the Turnitin dropbox in the Gradebook, Calendar Due dates or Assessment and Feedback folder in Course Content in your module.
Click on the name of the actual Turnitin drop box (with the
rocket shaped icon beside it).
This opens up assignment information panel at the side of your screen. You will then need to click on Launch, it will be located to the lower left of your screen, to open the Turnitin interface.
This opens the Turnitin dropbox, you can access information about the dropbox by clicking on the down arrow.
...
or just click on Upload Submission, this opens the Submit File menu
...
You can then upload your assignment by clicking on Choose file, or dragging and dropping your assignment or accessing it via Cloud Submission (i.e OneDrive)
...