Character Story Creation

Hello, I'm new to the SCP Universe. I'd say I've known about it since the "golden age", but at the time I wasn't interested in participating because it seemed too complex and difficult. And look, here I am asking about this beautiful Universe: How do I create a story/character within the SCP universe (it's not an anomaly SCP, but rather a story with characters or just one depending on the limits) telling the story of a character that I will create and what would be the limits of how I should write, for example: • What is the power limit of my character (in the context of positions and growth within the Foundation); • Can my character turn against the Foundation within the story? • Can my character have a psychiatric condition such as psychopathy, narcissism, and others? • What are the limits of interactions with SCPs if I want my story to be 100% canonical (if that is possible)? • I would not like to publish just once, but also publish test documents, experiments or even reports from them, could I? Is there a context guide for the SCP world? How could an ordinary citizen in the world (character) join the Foundation as an employee along with other friends? And where should I publish and how, the standard format for my story to be accepted?