Well, here's what you do, it's not complicated, although the course is rather involved, and does have a lab.
EAS 1601 (3-3-4) Habitable Planet (Fall,Spring)
Go to Georgia Tech and sign up for that class. Every single thing you just asked will be answered in the course of that class, based on ALL available evidence and with all available information to date. Everything from the forming of nebula and the eventual generation of the elements all the way from Hydrogen to the heaviest of the radioactive elements. The timeframe of it all, the formation of our universe, solar system, how atmospheric conditions were stabilized, why and when.... I mean every last question you just asked. Again, based on observation, experimentation and logic.
The only question it will not cover is how you were made. But I think this was well covered in middle school sex education, with the whole sperm, egg, uterus, so on and so forth. DNA, Punnit squares, other genetics topics....
I find it's often the case that people think that it is unknown how the soloar system formed, our sun all the planets, the elements, and eventual habitability of the one we call earth, as well as the evolution of life to the point where mammals classified as Humans came into the fray.
I sometimes wish I had never taken that class. Given my HORRIBLE inner turmoil with this topic up to that point, the existence of accurate, testable, and repeatable answers to questions such as the ones you just posed, without fail and without and "fudge" factor was a blessing if you will. I honestly enjoyed the class so much I received something like a 98 in it IIRC. Present knowledge of past events edges closer and closer to the origin of the universe every day. Guys doing work with the particle accelerators are generating the kind of energy needed to do the kind of testing that can keep pushing our view farther and farther into the past. As it stands, we are fairly well versed in the history of the universe up to around ~14 billions years ago IIRC. This goes beyond the scope of every question you just asked. The only one left unanswered is what was before that. And as I already stated, I'm okay with that. I'm not scared to say.... I don't know.