How do you change the oil on a 1995 Renault 19?

Remove filler cap from engine bay under car on sunp of engine there will be a square bolt, this needs to be removed (tool can be purchased from any good car shop) remove the screw and the oil will drain from sump, make sure you have something to catch all the oil. put plug back in and fill new oil in through the filler cap under the engine bay. renault dealership how much oil does a renualt laguna 2000 (w) hold.with new filter