Why are hydrogen, helium and lithium important and how did these elements come to be on Earth?

The three elements: hydrogen, helium, and lithium are important because they are the building blocks of "normal matter" in the universe and play key roles in the formation and evolution of stars and planets. These elements were forged about 13.8 billion years ago, half a million years after the universe's creation. But even before this, fundamental forces and particles were formed. The process of element fusion led to the formation of galaxies and stars. The first-generation stars reached the end of their lifecycle seven billion years ago, and during this phase, many of the elements up to iron were forged in a process known as nucleosynthesis. A few stars exploded into supernovas, creating the rest of the elements under enormous temperatures and pressures. After this, the elements drifted around in space and gradually formed nebulae that became the nurseries for new stars. The gases elements like hydrogen and helium collapsed to form the Sun, while most of the other heavier elements coalesced in the inner rocky planets, including Earth.