Step 0: Tell a specific person to call 911, or do it yourself if you're alone.
If the person isn't responding and doesn't appear to be breathing, move them to a hard, flat surface (if possible). Put your hands one on top of the other (both palms facing down) and interlock your fingers. Place your hands in the center of the chest (at approximately the level of the nipples) and push hard and fast, letting the chest recoil fully between each compression.
If you're pushing hard enough, you will feel popping and cracking as the bones and cartilage of the rib cage move/dislocate. If you're allowing the chest to recoil back up fully between each compression you really can't push too fast (going too slowly is the far more common failure mode).
There... those are the important bits of adult CPR (for the layperson).
The courses are hours long so that the Red Cross/AHA can justify the fees and sell textbooks.
All accurate but you missed the real step 1, which is arguably the most important - Check for danger. It was drilled into us repeatedly in our course because it's extremely obvious but always easy to forget during a situation.
Our first aid teacher told us a lovely story of a child on his bike who got zapped by a downed power line. The next two family members trying to help him also died because they just rushed in. Not a great day for them.
In other situations, something as simple as pulling the park brake in a traffic accident can save a world of problems. Regardless, don't even get close enough to physically check them if you aren't sure it's safe.
There are certainly special considerations, but in the vast majority of situations where CPR is necessary, there is no external hazard to worry about, it's just Uncle Jim's diet and lifestyle catching up with him.
Often it's obvious, and checking takes no more than a second or two. It's just important that you do it.
Even if you find Uncle Jim on the floor at home, don't run in assuming a heart problem because maybe he tripped on some water and you'll do the same :) But if he starts choking right in front of you, go to town.
I don't disagree with you, but as someone who walks into a _lot_ of emergency scenes, it's really rare for there to be a hazard to worry about. Is it a thing you should consider? Sure. In reality it doesn't come up often enough to warrant "top billing" in a high level overview of how to do chest compressions.
In any emergency scene, the first thing to do is check for traffic to prevent the victim or yourself from getting run over (sometimes merely because you need to cross the street: while running to provide help in an emergency situation, you're likely to forget looking both ways).
If any one of those emergency scenes was outdoors and you didn't think of this, you're doing it wrong. And even if you've always remembered to do this yourself, it's essential that you explain it to others so they will remember it as the first thing to do.
Step 0 is the really high-yield tip here because it applies in so many emergencies. The natural shout of "someone call 911" is so often less effective: even if folks aren't halted by outright shock or confusion, their disorganization and/or assumption that somebody else will do it introduces miscommunications and delay. Nearly everyone takes to direct, simple instructions much better and faster.
How to call an ambulance, what kind of info to give, how to put people in a safe position, how to determine if they're breathing or not, how to protect yourself when offering first aid to someone else.
The American Red Cross has Adult CPR/AED/First Aid classes where the classroom portion is only an hour. There's an online component that you have to do beforehand, so the whole class is probably closer to 4 hours, but I think if you took only the classroom part you'd come out with a decent idea of how to perform CPR.
They listed three things, and they're all different.
Choking & CPR in an hour - easily. When I did my course it was a few hours but in a smaller group there'd be no problem covering it in less time. Though to be fair, we did have to read a document and answer a 70 question assessment before being allowed in the room.
First Aid? Probably not. I did a full day course. Here in Australia that includes bandaging for snake bites, what to do for jellyfish (don't pee on it, thanks), how to handle crushing injuries, etc. Apparently in the US they focus more on weapon trauma wounds though we did a bit of that too.
A broad first aid course will take more than an hour. (The Wilderness First aid courses I've taken are a full weekend.)
However, you can cover a lot of the basic things you're likely to encounter in civilization pretty quickly (if very cursorily). Probably most important is the basic approach to take, things to watch for, blood safety, etc. It's not going to be a real first aid course but a quick familiarization of things to watch for and actions to take. (Cleaning wounds, etc.)
What can you teach in only an hour? I work with some people who teach basic first aid, and the shortest course any of them does is 4.5 hours.