Exemple of mods load order with 1259AD
Little mistake: after captivity event there is default captivity event

Follow instructions from Immersive Battlefields custom Horn Addon.

For Immersive Battlefields 3.1.4 or before: Put this mod folder "Immersive Battlefields" in "modules" folder of the game and overwrite.

Put this mod folder ImmersiveBattlefields in modules folder of the game and overwrite (possible to custom with the global folder)
For Immersive Battlefields 3.2.2 and after

Put this mod folder ImmersiveBattlefields in modules folder of the game and overwrite
For Immersive Battlefields 3.2.2 and after