Question Logic behind fps animations

Hello!

Im developing a fps game and I came to the point where I needed to use blender which I have zero experience in. All my items in unity have ID and Im taking them from world to my players (empty game object) inventory in my players camera. The thing I dont understand is where should fps hand stay? Same place where my inventory is? All animations are going to be in same fbx file or is it going to be seperate fbx? Does items and hands needs to be seperate in blender?

Thanks!

 

Like arm is getting cameras way. Perspective is not good etc...