Create an horse idle animation (24sec) in 3ds max and export that in FBX format for Unity

What you will get from my side is, A rigged horse with 3 premade animations (already purchased from https://www.cgtrader.com/3d-models/animals/mammal/animated-horses-3ds-max) and you have to create an idle animation in 3ds max and you have to export all 4 animations in FBX format for unity.

Animation reference: https://youtu.be/xKaD76wdMNU?t=13 , duration (0:13-0:37)