Server Gameplay Flow
The server is in charge of driving the flow of gameplay. It is the server's job to notify clients that it is time to travel to a new map, when gameplay starts and ends, along with actor replication updates, etc.
The major framework portions are mostly out of the scope of this document, but we can talk about some of the additional multiplayer nuances introduced when dealing working with certain classes.
Gameplay state and flow are generally driven through the GameMode actor. Only the server contains a valid copy of this actor (the client doesn't contain a copy at all). To communicate this state to the client, there is a GameState actor, that will shadow important state of the GameMode actor. This GameState actor is marked to be replicated to each client. Clients will contain an approximate copy of this
GameState actor, and can use this actor as a reference to know the general state of the game.
For a more details explanation of GameMode, please see the GameMode documentation.