Hi sorry for the post but im new to all this and i cant figure out what is wrong with the script its an amnesia type script where u can drag the doors etc if someone could help me would be greatly appreciated

Right im getting this error in unity.......
ArgumentException: Input Button Grab is not setup.
To change the input settings use: Edit -> Project Settings -> Input
DragRigidbodyUse.FixedUpdate () (at Assets/Custom/Scripts/DragRigidbodyUse.cs:71)

The part of script that apparantly needs changing......
if(Input.GetButton(GrabButton)){
if(!isObjectHeld){
tryPickObject();
tryPickupObject = true;
} else {
holdObject();
}
}else if(isObjectHeld){
DropObject();
}

if(Input.GetButton(ThrowButton) && isObjectHeld){
isObjectHeld = false;
objectHeld.GetComponent<Rigidbody>().useGravity = true;
ThrowObject();
}

if(Input.GetButton(UseButton)){
isObjectHeld = false;
tryPickObject();
tryPickupObject = false;
Use();
}
}

Thanks in advance for help.