Kbin doesn't have as much of this because it's simplified quite a bit. It's one reason why I recommend Kbin to newbies, because it gives you a giant "sign up" button immediately.
But to answer your question:
Instance: a server that hosts everything. You and I are on Kbin.social, which is an instance. Another Kbin instance is fedia.io. Kbin has relatively few instances. Lemmy has oodles (Lemmy.world, Lemmy.ml, sh.itjust.works, etc.). Lemmy actively encourages people to spread out over many instances.
Magazine/Community: If you're on Kbin, I'd hope you know what a Magazine is. Lemmy calls them Communities. Reddit called them Subreddits. They're all basically the same - buckets for people to make posts about certain topics.