Nope don't feel bad - it's totally understandable. Kbin is new, so the documentation is lacking.
Almost all content on Kbin, including users, has a follow / subscribe button in the sidebar beneath the magazine or user description. There's also a block button. These buttons can be used on almost all Kbin content, so it's very powerful - after spending about a week adding subs, my Kbin feed is far more active than Reddit was, even at its height.
Kbin breaks down your content into Magazines, Microblogs, and Threads. Magazines are synonymous with Communities on Lemmy, or subreddits on reddit. Microblogs are where the Mastodon Toots go, and how you interact with instances based on that architecture. Threads are just like posts on reddit, and can be text only, a link, a pic, or a video (although it seems video is still under development).
The best place to start getting subscriptions are in the magazines section:
...which lists all of the currently federated communities. Putting a domain search into the search bar will bring up all magazines in the instance on that domain:
This domain searching is extremely powerful, especially when you use the domain section (which can be hard to find) - you can get a breakdown of any domain currently federated on kbin by using the following link:
...where you'd put the domain you're interested in in place of 'lemmy.world'. You can then subscribe to the entire instance through that feed, or block it f you'd like. This also works for standard domains as well: