When you upload and submit your notes, a link will show up. You'll also be provided with a sample message (which has the link inside it). This link is unique to your materials, and you'll be able to send it in a mass message to your classmates through the class messaging tool (Blackboard, Canvas, Moodle, D2L, etc.) that your school uses.
If you're not sure how to use your class messaging tool at your school, just click the yellow-orange button that's inside the green box (next to the sample message). That will take you to a step-by-step tutorial of how to share the link.
The green box with the tutorial link will only show up on materials you are required to share with your classmates.