As a general reminder, if you plan to credit to DL and use DL status - if you have a AF/KL Flying Blue account, do NOT log into your Flying Blue account when looking up the reservation on the AF/KL website otherwise your DL FFN will be overwritten by the Flying Blue one.
Once you booked your flight and provided Delta FFN, you can manage your trip by clicking "My Bookings" and entering your Booking Reference and Last Name. Then you can select seats and verify number of included bags according to your status.