Don't have a picture, but...
The Neutral Safety switch is at the top front. The reverse light switch is towards the rear of the main case on the driver's side (as mounted in the vehicle).
Don't know about a "black ball" on top, unless it is the vent.
The fill plug is also on the drivers side. It has a 3/8" square hole for your ratchet to fit in. The drain plug looks the same but is on the bottom.
To fill it up, (car level) remove the fill plug, get a hand pump for your quart bottle and pump in fluid until it just starts to come out. IIRC, just shy of 3 quarts. Put the fill plug back in.
Another way is to fill it on the bench before install. You will need a tail shaft plug, and you will spill a little when swapping in the drive shaft.
Good luck,
Scott