In addition to what @Barbarian@lemmy.ml mentioned about changing the filter and searching, you can link it from your own instance like so:
https://lemmy.ml/c/gaming@beehaw.org
You can also grab the URL to any community or post on another instance, return to your own instance, and paste the URL into the search bar. If you’re the first person to ever search for that server it might not find anything at first, but it’ll fetch the data and probably work in a couple minutes.
I still use reddit (for now) but I’m very much enjoying the smaller community feel on beehaw, while being able to join in on conversations in other instances whenever I feel like it.
There have been some stability issues on most of the more popular instances because of the sudden influx, but of course that’s to be expected and I just take it as a hint to get off the internet for a while, lol