Once you have signed in, you will see the My Projects tab. On the right-hand side, click on the +New Project button:
Choose citation style and level; name the project. Your teacher will instruct you as to what style and level to choose, as well as what to name the project:
You will now see your Dashboard, where you may enter your assignment (under Research Question) as well as see the last time your project was accessed and worked on. Under Sharing and Collaboration-->Sharing, you may share your project with your teacher's dropbox by clicking the link Share with a project inbox. Your teacher will tell you the name of the project inbox to enter.