Where are Inputs located?

TKInteractor script

This will have the KeyCode reference for the system

TKItem script

void PickupInput()
{
    if (canInteract)
    {
        if (Input.GetKeyDown(interactKey))
        {
            ItemAction();
        }
     }
}

TKInventory script

private void Update()
{
    if (Input.GetKeyDown(openInventoryKey))
    {
        OpenInventory();
    }
}