How do setup Multiplayer(dedicated server)?

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 :/)