The game will tell you where it is, generally. It won’t give explicit instructions on how to get inside. There are breadcrumbs though.
I actually got inside without trouble, and then got all the way to what I assume is the end of the dungeon before getting very dead. I thought I was pretty well-equipped for it but it looks like I’ll have to revisit that idea…
Well, that’s way more information than I expected. Again, thank you everybody for your help!
I believe all of my outstanding questions are now answered. I’m not usually a forum kinda guy but everybody here seems shockingly reasonable for a games forum so far*, so I’ll stick around. I’ve noticed some interesting projects for people hosting their own servers with Python tools and Docker images, both of which are my kinda jam, so hopefully I’ll be able to help somebody out with that kind of thing eventually.