the description said there are 10 animations (weapons + arms: - (10) Animations (Walk,Sprint, Fire, Reload, Aim Down Sights, Aim Down Sights Walk, Aim Down Sights Fire, Raise, Lower) ) and there is a vid of it posted by ironbelly :
start with the basic, in case you accidentaly remove some content.
go to your library, remove the local content from your vault for that asset, and reinstall it.
I don’t own any ironbelly content, so I don’t know how they work. but as suggested, you should first ask the asset creator.
And last, for the few I know about animating; for rig and animation you edit:can’t just mix rigged asset and animation “AS IS”, it’s not that easy. It’s not a plug’n play thing. (except when specifically designed to)