We meed to get to the Hongik University exit (closest is the blue line, but I guess green will do..) from ICN, arriving late afternoon on a Friday in July.

What is the best option? I think there's the airport train but I wasn't sure if there were multiple kinds, seems like there's something called AREX and then some other train(s) into the city?

Four of us will be traveling, all with bags, though probably just one-carry on size bag.

Thanks for any advice you can provide.