How to handle animated arms & guns

Probably no the place to post this but the "Animation" thread never gets answered. Anyway, I picked up some very nice animated hands & guns (https://assetstore.unity.com/packages/3d/props/weapons/animated-hands-with-weapons-pack-132915). I was wondering in what capacity do people use these assets? I mean I'm looking to create a FPS but do I have to write it myself or is there a decent FPS platform these arms can be targeted on?

Thanks