Welcome to the fediverse!
I see you've figured out that thing with the multiple instances already, so here's another point that surprises new people here: search only works on hashtags and user names (remember that when writing toots you want to be found).
Also, I'd recommend to write an introduction toot for people who don't know you yet using the hashtag #introductions. People actually read this hashtag :)
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!