Learn about which part specifically? I’d argue that IPv6 is essentially IPv4 with reduced complexity (due to stuff like NAT no longer being necessary since address space is large enough). The basics of how smaller connected IPv4 networks work pretty much extends to how IPv6 works across the internet with a few differences such as link-local addresses which are only valid in the same network.

If you mean Privacy Extensions, that’s part of SLAAC, which is a way of how devices in a network can get an IP address (the other being DHCPv6, which afaik works pretty much like DHCP in IPv4). Here, the router only announces the local network prefix and hosts assign IP addresses themselves, instead of the router assigning an address to each host. This works due to networks usually being a /64 block which is a large enough address space for IP collisions to be very unlikely (and in case they happen, the colliding hosts can resolve that automatically).

That’s as far as my understanding goes anyway, I’m far from an expert, just someone who has set up a Linux home router from scratch so I’ve had to deal with this stuff :P