Good points from other users.
You’re kinda asking the wrong question.
Where to start writing? Wherever you are when you write.
Where to publish? Seems to be what you’re looking for—
You’re likely an unknown author. So you are going to have to figure it out yourself In terms of marketing
Do you just want your stuff out there? You can put it almost anywhere
Do you want people to find you? Then you’ll need to market yourself (and yes I just threw up a little writing that)
It will be up to you to get people to find and read your stuff , sorry but yeah you mostly have to market yourself
So yeah put your page in there when you post your content here, and blue sky, and everywhere. Make a podcast of you reading your stuff, make it easy to share so new people can discover you.
Self published books and print on demand— worked for Andy Weir (the Martian) and Hugh Howey (Silo) and 50 shades of gray
Good luck