Took me some time to get it figured out for Steam Deck as well. If you're still having trouble getting things working, try something along the lines of this guide. It's what worked for me.
Think about things from the point of view of someone who has never used Reddit or the fediverse, but you've heard about them both from recent news articles and want to see what they are about....
The thing that helps Kbin the most is that it is, by far, the easiest to understand. Googling "Lemmy fediverse" gives a bunch of various links to other Lemmy instances, which are presented in a way as if they are separated from one another. Kbin appears as one site, one location for content aggregation. Although that "goes against the idea" of decentralization, most users are currently looking for their "one home to replace their old one home". The more users flock to one area and learn how it works, the more things will begin to take their proper shape, so to speak.
I'm still learning the ins and outs of this place and the others, but part of me thought that was the feature of being federated. User accounts could seamlessly transfer from one instance to another.
Looking further into it, it looks like that feature exists for content, but not so much for accounts.
Fediverse won't replace Reddit as long as Lemmy is the main platform being promoted (kbin.social) en
Think about things from the point of view of someone who has never used Reddit or the fediverse, but you've heard about them both from recent news articles and want to see what they are about....