The most direct way to share your work with classmates is using the Messages tab:

In the Messages tab, click on the folder symbol next to the Send button, in the bottom of the page.

Choose which file you want to share in the chat and click on Select.

It will show above the message field. Write a message telling everyone what the file you are sharing is about and click on Send.

You can also upload a file directly from your computer and share in Messages Tab:

We encourage you to participate in the Messages tab a lot! Communicating and sharing go a long way in getting the most out of your program experience!