Your username is from lemmy.world so just go to https://lemmy.world and that will be where you would log in
The “instance” is where your user is held - that’s lemmy.world. Any other instance, like lemmy.ml or sh.itjust.works or any of that won’t let you log in because those instances don’t have your user in their databases, but you can interact with them from your log in through lemmy.world
Premium’s been a thing for a long time, it used to be Reddit Gold several years ago. It also used to be cheaper, $3.99/mo but it went up multiple years ago.
They might be pushing it hard right now, though. Not sure. Maybe they’re trying to entice the people who were paying for 3PA features to pay Reddit instead or something.
I currently have premium, ad free is the only way Reddit is palatable even before all this went down and I bought it ages ago when I wanted to support a thing I used every day and also have had a couple awards that extended it, it expires in August. I won’t be renewing.
https://lemmy.world/c/therewasanattempt would probably appreciate this and it’s so new there’s nothing there yet.
Cisgender means the person has a gender identity that matches the sex they were assigned at birth.
If you are a man and you were assigned male at birth, you are cis.
If you are a man and you were assigned female at birth, you are trans.
Non-binary can mean anything from not having a strong specifically male or female identity to closer to switching identities (bi-gender falls closer into this) to just having a lot of serious fluidity, but typically speaking at least part of the time the identity doesn’t match the assigned sex at birth.