What Subreddit would i post to? and how would i format it?
Probably gamedev or indiedev subreddits, theres one for itch but its really inactive and and gets little interaction.
I'd say, don't straight up advertise your game, show a little bit of gameplay of it and talk about your experience, then post in the comment a link to the page for anyone whos interested. Game adverts tend to not do too well on their own.