You normally won't have anything to declare. You would have just Clothes and personal belonging. Then ask at the counter where to go next. Boarding You will proceed towards the Gate Number they gave at Check-in time. Gate number is also on the Boarding Pass.
All gates are on lower level.
You might have lot of time. There are places to sit. There are lots of shops also, just to look at. X-say their hand baggage. Then you have to wait in a hall till they make announcement for Boarding.