Who would use this? Students.
What is it? A tool within D2L to see assignment instructions, submit your work and view scores/feedback.
When would one use this? Usually when you have an assignment in any of your courses, you will submit your files or links here.
Where can I find this stuff? Under the assessment tab in D2L.
Why should I use it? So that you (and your instructors) have a central space to submit assignments and receive feedback on your work.
How do I use it? Here are the steps.