Amnesia style

soo im interested how to make i can drag and fire object like in amnesia
any ideas?

Learn some basic javascript or C.

Heres a basic javascript I created that makes an object follow your mouse.

var followingObject : GameObject;

function Update () {
  var v3T = Vector3(Input.mousePosition.x, Input.mousePosition.y, 3);
  v3T = Camera.main.ScreenToWorldPoint (v3T);
  followingObject.transform.position = v3T;

As for the shooting, you could use a RayCast system. Look up some tutorials on google or YouTube for that.