How do setup Multiplayer(dedicated server)?

Hello,
i’m new in UE4 and i’ve made few things but only localy, i’m sadly not interested in “single” player becasue it doesn’t motivate me and i would like to make a multiplayer game.

My first question would be, how do i set the “Server Blueprint”? Where do i need to add my blueprints which will run on the server side?
I want now to replicate the movement of my planes. (But it isn’t working :/)