Watch the commuters come and go at Skypier. Alternatively, purchase your own ferry ticket and see where the route takes you.
You'll be spoiled for sightseeing choice in Chek Lap Kok. Skypier is an ideal place to begin here, but there are loads of other worthy spots to visit. Ngong Ping 360, Po Lin Monastery, and Citygate Outlets are near the ferry passenger terminal and will fill in your day nicely.