a) It means that there won't be any jet bridge and you will arrive at a remote bay and bused to the terminal. The international terminal arrival hall will be partitioned and one side will be used as domestic arrival. Also, you will not have access to anything on the international terminal until you checkin for the international flight.

Since your arrive at 2.30 PM it will take atleast 30 minutes for you to get bused, collect your luggage and assuming you check in for your international flight at 8 PM that leaves you with only 5 hours to kill. Best thing is get a book and there is a restaurant where you can spend your time. http://www.tajsats.com/srv_services_restaurant.htm I think this one is located between international and domestic terminals in the second floor.