I think this was introduced previously, but I noticed I passed the 2/3rd century mark and may need one of you youngster know how to do this properly. I hope you never need to know this but I would rather you know it and not need it than need it and not know it.
This short video illustrates the best demonstration and gives the simplest explanation of exactly what to do if someone near you collapses and is presumably having a heart attack. You could very well save the life of a friend or loved one. Someone you share this video with might save your life!