What is the first step Vickie should take when using the AED?

Turning on the AED is indeed the first step Vickie should take when using the device. This is crucial because the AED needs to analyze the heart rhythm of the patient to determine if a shock is advised. Once the AED is activated, it provides audio and visual prompts that guide the user through the next steps, including where to place the pads and when to deliver a shock if necessary.

Additionally, while attaching pads and calling for help are essential steps in the overall process, they should follow the activation of the AED, as this ensures that the device is ready to assist in a timely manner. Hovering hands over the patient's chest would not contribute to the immediate lifesaving actions needed in this scenario since the AED clearly directs the user on how to proceed after power-up. Thus, activating the AED first streamlines the response to a cardiac emergency, making it a vital initial action.