So you want to ground wiring in an old house. This is a very easy process that shouldn't take you more than five minutes.
Locate your outdoor power transformer.
Locate a nearby water tap. If there isn't one in the vicinity, you will need a metal pole. If this is the case, insert the metal pole in the ground, the deeper the better.
Shut down the power to your house to avoid electrocution.
Attach the metal wire to the power box or the wires leading out of it.
Attach the other end of the metal wire to the water tap or the pole.
Attaching the wire to the water tap is a better idea; water pipes run deep into the ground.
It's best to hire a professional to handle these sorts of matters. But, at the very least, have someone assist you in case of emergency.