FYI, i see a lot of users joining, but not many people are actually subscribing to the communities. Subscribing to the communities you like will help them grow within the fediverse and be easier to discover!
Follow the instruction on the blue block on the right:
You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !pf2general@pathfinder.social
Yes, the networks all "federate" together. Basically they all talk to each other and share information. For the networks to see each other, though, they need to be made aware of each other, which can take a bit of poking around to do.
As for seeing different communities in one page: Yes. Go to the home page of any instance and click on the "all" button at the top (right next to local). There's also a button to only see a feed from communties you are subscribed to (both locally and on other servers)
Edit: and looks like we're already federated with pathfiner.social, so you can see and subscribe to all their communities with your account here. You can just use the search feature at the top to find em.
yep, basically. The "/c/" is literally the equal of "/r/" on reddit. If the community is local, then the "@<url>" part can be omitted. So like the dndnext community here is just https://ttrpg.network/c/dndnext