How to make Maps Game modes?

Hi Brian,

following this documentation you can use ?game= suffix when loading a map to override the default GameMode to use like /Game/Maps/MyMap?game=MyGameMode.

How do I make a game mode for a map?

So if i have a level how can I make multiple copies of that level but all with different game modes that you can play?

Example Team death match, Death match, Survival, Free roam, Racing ect.