SQ flies from Singapore Changi Terminal 3. My flight was SQ 306, which departs 0110hrs. As I had completed my work for the day, I went to the airport rather early. Take note the roads in Singapore are more congested during the evening peak hours so the ride took a bit longer than usual, but still nothing too extreme. Taxi rides in Singapore are also fairly inexpensive, my ride cost about 30 SGD for a 32km run. Check in for Business Class at Changi Terminal 3 is at Row 5. (common row for all Business class flights). It was empty when I got there, so check in was a breeze. Here is a short video of the check-in area.