If you do not have a driver's handbook (which will have the information) then you could go to somewhere like Halfords, who will have all the info ref what oil you need for your car.

As for where, you will need to either have access to a PIT or a car ramp/lift as you need to get underneath the car, the oil filler plug will be on the side of the gearbox, and you should only fill untill it dribbles out of the filler hole.