If you are really looking for facts about the Scientology religion and not a lot of internet /media generated disinformation and complete rubbish ( like the Xenu thing, for example ) I recommend the book "What is Scientology"
this is a comprehensive encyclopedia that will answer all your questions. We do not have a "Creation Story" in the same way that Bible based religions do. Like Buddhism doesn't have this kind of story either.
Here’s a factual description for you (From an actual Scientologist):
Scientology is a new religion. It is an applied religious philosophy. By “applied” is meant that it is for use in life and living. You actually use it in your day to day life to change and improve existing conditions. It is a practical religion.
All religions if you study them have a basic philosophy, but they also have certain dogma, rituals and observances and a certain faith or belief is required. There is nothing wrong with this , but Scientology is not that kind of religion. It acknowledges the principle of God or the Supreme Being but does not try to define or describe this principle, leaving it up to the individual.
It is also not a messianic religion. This means there is no worship of prophets or messiahs or gods. It is not belief or faith based. In Scientology a truth is true for you according to your own observation and experience .
The dictionary definition that applies:
Religion: The spiritual or emotional attitude of one who recognises the existence of superhuman power or powers.
The most basic principle of Scientology is that YOU are your own immortal soul, that this is not a thing you have but what YOU actually are.
Scientology believes or considers that Man is basically good. This is different from many religions that promote that he his natively evil or bad unless “made” good.
The whole purpose of Scientology knowledge application and procedure is to increase an individual’s understanding and awareness of himself as a spiritual being and to rehabilitate his native abilities and potential.
When you do this there sphere and zones of his positive influence increases and moves outward into his life , his family and friends, his groups and Mankind of which he is part .
How this result is achieved is the “technology” of Scientology, which was developed by L Ron Hubbard from discoveries he made after extensive research into the field of the mind and the human spirit.
Some of this knowledge was already existing in the sacred lore of ancient texts like the Veda or Vedic Hymns going back 10,000 years. New and additional discoveries were made about the nature of the human spirit and fully recorded and codified .
Scientology’s closest spiritual ties with any other religion are with Orthodox (Hinayana ) Buddhism with which it shares an historical lineage. But even here the relationship is based mainly on friendship and the recognition of the being as a spirit rather than any organizational ties.
L.Ron Hubbard published 18 basic books from 1950 to 1955 to fully communicate the basic principles of Scientology, the path of his research and the technology that he developed from this.
He completed all his research before his death in 1986 and left all his materials and copyrights to the Church of Scientology’s Religious Technology Centre along with most of his personal estate when he died.
The Church of Scientology is currently established iand operating internationally in over 160 countries world wide. However it is still a new religion, less than 55 years old.
The true story of Scientology as a religion goes like this:
1. A philosopher developes a philosophy about life and death.
2. People find it interesting.
3. People find it works.
4. People pass it along to others.
5. It grows.
This is just an overview.
L.Ron Hubbard explained fully the theology and technologies of Scientology in more than 500,000 pages of writings, including dozens of books and over 3,000 tape recorded public lectures. So it’s not possible to fully answer your question on this forum, but I hope this helps.