There's a lot of attempts at investigating those questions. Here's a couple of pages I'd recommend to peruse:

https://en.wikipedia.org/wiki/Cosmic_time

https://en.wikipedia.org/wiki/Chronology_of_the_universe

If you're into podcasts at all, I'd strongly recommend Crash Course Pods: The Universe. The first (full) episode goes into detail on that first fraction of a second in our universe and it's pretty enlightening without being to thick on the math.