In a terminal window start the editor as follows:
$ emacs
A new editing window will open up. Click on the Help menu and select Emacs Tutorial. Start reading from the top. You can stop when you get to the section about "Buffers". As you read about each command in the tutorial, give it a try. This tutorial should take about 20-30 minutes to complete.
I have created a short Emacs Summary to help you remember the most frequently used commands. You may want to print this and bring it with you to class the first couple of weeks.