NetworkServer.AddPlayerForConnectionthen it will automatically be given authority.
AssignClientAuthority. This can be done by calling
AssignClientAuthorityon the object you want to give authority to.
identity.RemoveClientAuthorityto remove client authority from an object.
OnStopAuthorityfunctions to be called.
identity.hasAuthorityproperty can be used to check if the local player has authority over an object.
identity.connectionToClientproperty can be check to see which client has authority over an object. If it is null then the server has authority.