Issue:

You want to see students in MSS who are not enrolled in your class
Solution:

Navigate to the School View > Student top tab in order to see all students in your school
When you log onto MSS as a Teacher you are defaulted to Staff View where you can see information relevant to your classes. Your class list will show up in the Student top tab as shown below.
To get to School View click on the dropdown menu near your name in the top right corner that currently says Staff View. Click on School in the dropdown menu.
Click on the Student top tab to view a comprehensive list of the school's students.

From here you can filter and print reports.
Click the filter button directly to the right of the search box and it will open a dropdown menu with many ways to filter the student list. The most common filter will likely be "Grade Level = ?" or "Homeroom = ?"
To print the report, click the printer button. It is the farthest right icon to the right of the search box. Click "Web Page (HTML)" from the dropdown menu.
This will open a new window with the report generated. Right-click and select print.