CPR stands for cardiopulmonary resuscitation, which is a first aid technique used when someones breathing or heartbeat has stopped. It is a lifesaving technique that can help save a persons life in an emergency situation. CPR involves chest compressions and mouth-to-mouth breathing that help circulate blood and oxygen in the body, which can help keep the brain and vital organs alive.

Here are the general steps for performing CPR on an adult:

1. Check the scene for safety and form an initial impression.
2. Check for responsiveness, breathing, life-threatening bleeding, or other life-threatening conditions using shout-tap-shout.
3. If the person does not respond and is not breathing or only gasping, call 911 and get equipment, or tell someone to do so.
4. Kneel beside the person and place them on their back on a firm, flat surface.
5. Give 30 chest compressions:
   • Hand position: Two hands centered on the chest
   • Body position: Shoulders directly over hands; elbows locked
   • Depth: At least 2 inches
   • Rate: 100 to 120 per minute
   • Allow chest to return to normal position after each compression
6. Give 2 breaths:
   • Tilt the head back and lift the chin up with one hand.
   • Pinch the nose shut with the other hand.
   • Take a normal breath and cover the persons mouth with yours to make a seal.
   • Blow into the persons mouth to make the chest rise.
   • Give 2 breaths.
7. Continue giving sets of 30 chest compressions and 2 breaths. Use an AED as soon as one is available.

It is important to note that CPR steps may vary depending on the age of the person and the situation. For example, for children, the compression-to-breath ratio is different, and for infants, only two fingers are used for chest compressions.