After establishing that part, each node in the network do also share each other information and the node may keep the information in their own known-node local databases, so other or you can connect to each other. For a further detailed explanation, you can refer to:
https://developer.bitcoin.org/devguide/p2p_network.htmlSo when I'm connected to a node, not publicly routeable, does that mean I'm connected to it through another node?