The Jam Factory is 5 min walking from ICON SIAM. Or you can go to RIVER CITY and take a ferry at Sri Praya Pier, across Chao Phraya River direction Khlong San Pier. And it will take a 1 minutes walk from the pier to The Jam Factory.
Or you can take BTS and get off at Thonburi Station. From there, you can take a hired transport, such as Taxi, Tuk Tuk or Motorcycle Taxi and tell them to take you to The Jam Factory. It will take about 10 minutes on the road with regular traffic.
Google Map Search: The Jam Factory