Party Beacon? How does it work? o.O

Any news about documentation or tutorials? I would like to know what the party system can do, and what is already implemented and actually working. As overlawled suggested I am looking at UParty and UPartyGameState, but I still haven’t figured out a lot. Without the implementation of UOnlinePartyInterface, UParty is unusable, but maybe something can be done using beacon host and beacon client directly?