Hands-only CPR is a lifesaving technique used when someone has a cardiac arrest. It involves two main steps: calling emergency services and performing chest compressions. You should push hard and fast in the center of the person's chest, aiming for a rate of 100 to 120 compressions per minute. This method is effective because it helps maintain blood flow to vital organs until professional help arrives. Unlike traditional CPR, it does not require mouth-to-mouth breaths, making it easier for bystanders to assist in an emergency. Remember, acting quickly can save a life.