OS X Yosemite: Right-click
If you’re used to right-clicking on a Windows computer, you can use Control-click in a similar way on your Mac. If you have a Magic Mouse or other multiple-button mouse, you can configure the mouse to right-click the way you like best. On a trackpad, you can use a two-finger tap.
Open a shortcut (or contextual) menu: Hold down the Control key, then click an icon, a window, the toolbar, the desktop, or other item.
The options in shortcut menus depend on what you click.
Configure a multiple-button mouse: Use Mouse preferences. To open Mouse preferences, choose Apple menu > System Preferences, then click Mouse.
Configure a trackpad: Use Trackpad preferences. To open Trackpad preferences, choose Apple menu > System preferences, then click Trackpad.