Someone else already gave a decent explanation :)

Can you try these two guide pages and see if they help? They have some diagrams

fedecan.ca/en/guide/get-started

fedecan.ca/en/guide/lemmy/…/detailed-overview

So lemmy.ca and piefed.ca have different feeds altogether when I view them, are they two separate things then

They are two separate platforms, made by different teams. The feeds look different for a few reasons

• piefed.ca is brand new and so it is missing a lot of the content. As people start using it, the default logged out feed will start to look closer to other instances
• An instance only pulls the content that its users are subscribed to. When you make an account on an instance and you are the first person to subscribe to a community, hitting subscribe will tell your instance to start pulling in those posts. That is why every instance will be slightly different regardless.

I’m not really clear on how communicating freely between them works

Unlike Lemmy and Mastodon, which are somewhat different formats (posts in communities) vs. short text posts on a user’s profile), Lemmy and PieFed are more or less the same. So it should be a lot closer in experience. Whatever you can subscribe to, comment on, or vote on within lemmy.ca, you should be able to do the same on piefed.ca

Especially because we are running both instances, and so they will have similar block lists.