There is no right button on an Apple (Mac) mouse. Press and hold the Command ⌘ key while clicking the mouse button to emulate right-click. If you are using a Windows keyboard, hold the CTRL button while clicking the mouse button.

If you have tried holding Command/CTRL and clicking the mouse button with no effect, check that your System Settings allow right-click in all applications:

Mac Desktop

- Open System Preferences, then Keyboard & Mouse
- Select Mouse tab
- Set the the right mouse button to Secondary Button

MacBook

- Open System Preferences, then Keyboard & Mouse
- Select Trackpad tab
- Check the box for Place two fingers on trackpad and click button for secondary click
- Once this option is activated, place two fingers on the trackpad and then click the mouse button to right-click