Installation:
Download the the Combined or separate optional files you want and install using (NMM, Mod Organizer, manually or other).
NOTE: Mod Organizer will give the error "No game data on top level". Just click on the file name and right click on data and set as directory.

For manual basicly drag and drop the files in your Skyrim SE data folder. Paths are provided below just in case.
Place the files for first person in:
LOCAL DRIVE PATH\Skyrim Special Edition\data\meshes\actors\character\_1stperson\animations
Place the files for horse in:
LOCAL DRIVE PATH\Skyrim Special Edition\data\meshes\actors\character\animations\horse_rider\patch

Uninstall:
Delete/Remove the mod from your mod manager.
For manual delete the files (1hm_equip.hkx, 1hm_unequip.hkx, mc_1hm_equip.hkx, mc_1hm_unequip.hkx) in the path locations marked above.

Compatibility:
The mod overrides the vanilla used animations. Meaning it should be 100% compatible with EVERYTHING!

Credits:
Bethesda for the original 2 Handed animations in first person and on horseback.
Plus the the people who did this on the original skyrim: TixIssence and zGRD.