PieFed help

I've been using Lemmy a couple of months, and now trying out Piefed.

Questions about community subscriptions:

1. So by ticking the "topics" boxes during registration, I am now subscribed to a bunch of communities, right? Or am I subscribed to "topics"? Or "feeds"?

2. What's the difference between Lemmy-style communities and Piefed's "topics" and "feeds"?

3. How can I see which communities/topics/feeds I'm subscribed to?
   (I saw a list once, I think on the home page, but for some reason I've never been able to find it again.)
   Ah, I found https://piefed.social/communities but not through the Piefed UI, only via https://join.piefed.social/docs/user-guide/

4. How can I find the Communities list in the Piefed UI?

5. Re importing my community subscriptions and community blocks from my Lemmy account, what file do I need? Is it Lemmy > Settings > Export Settings: lemmy_user_settings_dateandtime.json ?

• 5.1 And will that overwrite or supplement my existing Piefed subscriptions?
• 5.2 Wait, did Piefed already include my existing Lemmy community subscriptions??? Or is it just luck/topic-picking-on-sign-up that they seem to be included among all the others?