Hi,
Im new on this engine, I don’t speak so much english, so let me try this 
I try to understand the multiplayer system, so I look than exist 4 key words (Client) (Dedicated Server) (OnlineSubsystem) (Sesions).
My question is, how I can use online subsystem to create lobby’s and game’s (Single’s)? To, if I create a lobby, invite any person to my lobby, and next search in matchmaking from sessions of dedicated server’s, but keep the lobby and view like “playing” to others players, and let join during a lobby playing (If team is from 6, and are playing 5, and one player has been invited before start playing, this can join to lobby, but not to same game server), like Battle Royale’s.
Thank you 