first download the map editor or rampage trainer
map editor: https://allmods.net/red-dead-redemption-2/tools-red-dead-redemption-2/rdr2-map-editor-v0-10/
rampage trainer: https://www.nexusmods.com/reddeadredemption2/mods/233
now just put the map in Red Dead Redemption 2\MapEditor\Maps
                                         or
                        Red Dead Redemption 2\RampageFiles\Spooner

Chuparosa project: https://www.nexusmods.com/reddeadredemption2/mods/794