For those who are absolute beginners, I would recommend mastering the two things first:
- Bodyweight squats
I believe these two exercises are the foundation of weight training.
Knowing the correct mechanics of bodyweight squats (ass back, not ass down) would serve you in good stead for future pursuits of weight training: barbell squats, deadlifting, heck... kettlebell swings even.
And there's a lot more to the humble pushup than meets the eye. Do you know that the pushup works your back muscles as well as your pecs? And it also activates your lats quite a bit. And of course, it also trains core strength.
Once you get decently good at these two moves I think it would be so much easier for you to learn other things.