Wow. Slowly! Three questions at once which all made me answer.
I will try to 'answer' one by one according to my abilities.
"Do you believe in the big bang theory?"
Do not know. So far no human has known the method for testing the hypothesis that the Big Bang was created by an entity outside our universe. The universe began to exist since the Big Bang and everything we observed in the universe came after the Big Bang, while the 'creator of the universe' is certainly not part of the universe.
"If (Big Bang) is not (creation), why is there only life on Earth? Do you think it's time we believe in supernatural beings? "
First, we do not know whether Big Bang is a creation.
Second, we do not know whether there is another life outside the Earth. For this, we have many methods to them it, including:
sending spacecraft to members of the Solar System other than Earth,
monitor whether there are strange signals coming from outer space (for example, alien radio broadcast signals straying to Earth), and
waiting for another life to meet us.
So far, no other life outside the Earth has been found, either in our Solar System or outside. There are many strange signals originating from outer space, but for the most part, they are just natural phenomena that can be explained by astrophysical phenomena.
Well, the next question
"If so, how do the elements that cause the explosion to occur?"
The human body consists of oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, and many other elements.
according to some info that I received initially in the universe, only hydrogen and helium are available. Stars are early generations of planets that are formed purely from these two elements namely hydrogen and helium, then in other stars other elements such as carbon and oxygen are produced. If stars have a large enough mass, stars can experience an 'explosion' called a supernova and produce various other elements. The material from the explosion can mix with clouds of hydrogen and helium gas that are common in the universe, then form new stars and planets. Including the Sun and the Earth.
know that, the building blocks of the Earth and everything in them — including humans — are provided by stars.
We know there are countless stars out there. Oxygen, carbon, hydrogen, calcium, phosphorus, etc. have been provided by stars. It could be that these elements form Earth-like planets, then form organisms that live on the surface.
But we can't find it yet.
that's some of my opinions, hopefully useful. Good luck