The universe began with a massive expansion. During this time, only the lightest elements existed like hydrogen, helium and very small amounts of lithium.
13.7b years ago
The first stars formed
They were made of hydrogen, helium and lithium, and they were much hotter and larger than the sun. However, due to the expansion of space, the first star is too fair to be detected by observatories.
~13.7b years ago
The first galaxies formed
~13.6b years ago
The Milky Way formed
This is the galaxy where the Solar System resides.
~4.6b years ago
The Solar System formed
This is where the Earth, Mars, Jupiter, etc... are at. This system revolves around the sun.
Our solar system formed from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a supernova. When this dust cloud collapsed, it formed a solar nebula - a spinning, swirling disk of material.
At the center, gravity pulled more and more material in. Eventually, the pressure in the core was so great that hydrogen atoms began to combine and form helium, releasing a tremendous amount of energy.
And with that, our Sun was born.
Keep in mind this timeline is currently not complete and missing a TON of info, hence its, uh, stubness.