Persona creating, what do i do?

I want to create my own persona, I know it sounds stupid but I love imagining scenarios in my head to take a break from reality, I have an idea on how I want my persona will be, it always seems to be the same character i play, and the more I think the more I want to write about this character ive created in my mind, about the songs they "wrote", about the personalities they have, the stuff ive carried in my mind since i started imagining these things, all that sort of stuff, but I literally have no idea on how to start. Does anybody have any tips or templates that might help me out?