The owner holds the private key to the chat room, and is the ultimate authority. There can be multiple owners in a chat if they each have a copy of the key.
Only an owner can change the topic or adjust the advanced settings. This is because the chat room topic and other parameters must be signed when packaged in response to a chat room gathering search.
These levels all have the power to ban users at a lower level. So an operator can ban a moderator, a manager can ban an operator, and so on.
Operators can elevate other users to moderator level. Managers can elevator other users to moderator or operator. The same rule also applies to lowering the level of another user, so operators can change a moderator back into a regular user, as can managers do to operators.
At least one user of moderator level or higher must be present in the chat room for new users to be able to enter and for the channel to be visible in a gathering search.
This is the default level for users entering the chat room.