Calling 911 is the right way to go. Activating emergency response system. And if you don’t make sure someone else does and tells you they have. So many times people assume someone else called and no one has.
There was a push at one point in time to teach bystander CPR, which focuses on compressions at a rate of 100-120 a minute with a little less focus on landmarks and more “middle of the chest and go”. It also taught that people typically have about 20 minutes of reserve oxygen in their venous system and that compressions continuously increased survivability by keeping the circulation going through compressions. Considering average ems response time in the US, it seemed to reduce confusion and encouraged more community response (not wanting to do mouth to mouth is a fear people have). Not sure if it’s still being taught, but it was fairly well received at the time.