Though there are many organizations that review the steps of CPR and ECC (Emergency Cardiovascular Care), the basic steps are consistent. Training is always recommended, but it’s noteworthy that “The American Heart Association recommends that everyone — untrained bystanders and medical personnel alike — begin CPR with chest compressions.  It's far better to do something than to do nothing at all if you're fearful that your knowledge or abilities aren't 100 percent complete. Remember, the difference between your doing something and doing nothing could be someone's life.”  - MayoClinic.org 

Here is advice on how to perform CPR from the American Heart Association (as listed on the Mayo Clinic site):