So how do you even start talking to people online?

What you want to do is left click the person you wanna talk to. Then a text box should pop up with some dialogue followed by some dialogue choices. Choose your answer carefully and remember to save often. That's what the space bar is for.

Usually, if you want to talk to someone who likes the same music/anime/whatever as you, you could start out by saying something along the lines of they're interesting and that you'd like to be friends (at the start at least, even if you plan for more). The more detail you put in, it could either get more annoying or more interesting, depending on what kind of person you are tbh. It's all up to luck, half of the time

I'm pretty inept socially as well. (Worst at talking on phones and going through drive thrus though) Online I'm a bit bette though. Like someone else said, send a message and if there is no response, it sucks, but move onto the next one. I find a good conversation starter to talk about something in there profile or one of their pictures.

Introduce yourself, find common ground, tell a few jokes, make small talk. Then see where you go from there, it's quite simple and usually works out in the end. For those who say "nice guys finish last" is wrong, there are those out there who think otherwise. Just be open minded!

Lol, just talk to them. I always start off saying hi, asking how they are whilst introducing myself and then I just plummet into wherever that rabbit hole happens to take me. I find being random and spontaneous and finding pretty much anything to talk about helps a lot but I actually avoid talking about anime at the start as I want to know people as some ordinary person learning other aspects of themselves before diving into the anime talk. Plus I'm sure a lot of people are sick of hearing the phrase "What's your favourite anime?" over and over so I avoid that. If they choose not to talk then don't bother with them imo. Talk to those who actually want to talk to you.