Likewise welcome to the forum!
I also have an S4 and was sure that the factory went over this with me when I collected my car. However in my poorly lit garage I struggled to find the dipstick tonight! Have to admit defeat and say that it's not obvious where the oil should be added. The manual does not show a diagram and is of no real assistance.
As regards oil the handbook mentions 0-30W, 0-40W, 5-30W and 5-40W fully synthetics as all being acceptable. Would imagine Castrol would be fine but know that the factory use Miller oils. Main problem is where it goes I guess!
Look forward to being enlightened by the experts on the forum as regards the oil filler!
Kind Regards,
Robert
