Make sure you have your key with you.
Opening the trunk
Make a single kicking motion under the rear bumper and move back.
A short sound response indicates that the trunk is about to open.
Note
Repeated foot movements cancel or reset the activation.
Closing the trunk
When you want to use the hands-free feature for closing the trunk, repeat the kicking motion once. A short audible response indicates that it's about to close.
If the function appears to be unresponsive, keep in mind that obstructions to the sensor such as mud can interfere with a proper response.