I believe that it opens at 8.00 or 8.30 a.m. and I would get there early as a queue can form quite quickly, one thing to remeber is that they have a seperate queue for 1st class, PE and frequent flyers and they then go before those in the economy queue, we got there early and were at MGM at 9.15 in the morning so had a great day without worrying about checking in at airport and queing there. If my flight was at 8.20 p.m. I would arrive at at least 6.00 pm depending on duty free shopping etc. they start boarding the flights an hour before departure and you will have security checks etc