in this tutorial Content Examples Sample Project for Unreal Engine | Unreal Engine 5.2 Documentation
The node, “switch has autority”, is included in a client program, but authority means it is called in server side.
At this point, I haven’t done anything in a dedicated server, so there aren’t logics made in the BP.
To know if it is called in a server, the logic should be in the server, isn’t it?
So, I’m really confused. Someone help me please.
I’ll try to explain this the best way I can 
Switch has authority doesn’t need to be in the server side only. Think about it like this. All the code you are doing, at least in blueprint, will be packaged for both your server (Doesn’t matter if it is a listen server or a dedicated server) and your client. So you have to code with that in mind. Switch has authority helps you distinguish if the instance that you are executing code on at the moment, is a server, or is a client (. Server does have authority on almost every actor in the game.
Does that answers your question? :o