Sure, this talks briefly about tags. I’m trying to find the guide for new users that was written early this week, but can’t at the moment. I believe it talked more about them. When posting on kbin, add tags to the tags field. Try to make them relevant and likely that someone has set their magazine or other instance community to look for it.
Edit: This is also how Related Magazines and Related Threads are pulled into the sidebar within magazines.
Edit 2: There’s also /m/gettingstarted but they don’t have a ton of stuff there, though they do link to that FAQ above.
Edit 3: To see if a tag will work for your purposes this is the link: https://kbin.social/tag/food where you replace “food” with whatever your tag is. This lets you see where people are posting about that as well as what kind of content will pull into your magazine if you use that tag in your magazine settings.
You use tags. You can see this for yourself if you want to know if a tag will get picked up and where it might either pull from or go to: https://kbin.social/tag/food. This FAQ talks about how tags work.