New to mac? All of your system settings will be conveniently found in the application called System Preferences. The quickest way to it is to click the black apple at the top left and click System Preferences.
From there, click trackpad. The rest should be obvious; read each setting and view the demonstration clips.
The option you want is Secondary click. Use the pull-down menu to set to "Click or tap with two fingers" and all you have to do is do a tap, like normal, but with two fingers at once.
Bingo.