Hi reglo

go to etihad website and chose to book flight using miles. Type in flights you want to travel on and if there are seats available in the first column then they are also available for upgrade. If you want to double check you can ask call centre to check availability. Once the flight is ticketed the call centre can process upgrade immediately.
Even if the award seats are gone you still have a chance to upgrade at airport if there are J seats available. However option 1 is better as you then qualify for chauffeur drive on departure and arrival at destination.

Hope that helps and enjoy the trip, maybe you can do a trip report on it!