(disclaimer: I’ve made this as a compilation of various documents and videos, and some from my own conjecture. None of this should be taken literally, it might not have or might not happen.)
Part 1: The primordial era
The beginning: The universe is in one single gravitational singularity. So you, as an observer, are inside that singularity. At this point, there is nothing. There is just matter and energy inside one infinitely small point.
Then suddenly, matter starts to expand.
.00000001 seconds-100,000 years pbb (post-big-bang): In a stunning but still incomprehension able display, the universe begins to expand. In an extremely hot quark-gluon plasma, trillions of degrees hot, the elementary particles of the universe begin to form. In this extremely hot mix, many things are indistinguishable, such as the electromagnetic force, the strong force, and the weak force. All of them are joined together in a single united force.
Slowly, the quarks collect the gluons together to start forming together into larger and larger particles.
Protons come together, just fractions of a second after it all started, and then atoms.
Thus starts atoms.
However, virtually all of the matter is in hydrogen form. It will take fusion to create larger particles.
100,000 years- 300,000,000 years pbb: Now is the cosmic dark ages. After the universe created atoms, they created a universal uniform gas that obscured all light. However, the gas is not completely uniform. Gravity, the single most important crusader in the universe, is always at work. Particles are always pulling each other together. After 300 million years, significant clumps of matter have drawn together. Then, under their own gravity, they become dense enough to heat up, and eventually ignite. The Cosmic Background Radiation begins.
The Era of Stars is begun.