How does the gas get into the sun?

Answer 1

Initially, 5 billion years ago, a large collection of Hydrogen gas accumulated over time to form a large body of gas. When temperature gets extremely high in the core of this body, nuclear fusion starts, using the gas as fuel. So, there was already gas in the first place, and the star dies when this fuel runs out.

Answer 2

The gas that makes up the Sun is primarily hydrogen and helium that was present in the early universe. These gases were drawn together by gravity, eventually forming the Sun through a process called gravitational collapse. The high temperatures and pressures at the Sun's core then initiate nuclear fusion reactions, where hydrogen atoms combine to form helium and release energy in the form of light and heat.