Jmol is an open source Java-based program for viewing molecules.
Jmol can be difficult and time consuming to install. Try using the web based JSmol before attempting to install Java and Jmol. You will still need to download the molecular files needed, but your professor should make them available via Mycourses.
JSmol allows you to open (click the open link just below the image viewer) files that have been downloaded to your computer. Once selected you will see the Choose file option and will be prompted to Open the file location of the molecules. Once selected, hit the load button to view the selected file.
Before You Start
In order to run Jmol, you will need to install Java 8 in order to run it.