start by going to immigration , tell you need documentation to renew both licences , at the same time get a copy of your passport / visa to take to the transport office ...i took our housebook , but wasnt required because immigration put your address etc on their document ...no med cert required either , no appointment needed either , i just presented in person and followed their instructions .. all offices are different tho , so if your close enough might pay to go down and find out what they require , just to be safe
I went to Pranburi transport today ...had the necessary docs , watched the hour long video , did a color blind test , then paid the 500 baht and walked out 20 minutes later with a 6 year renewal ... done ...no medical cert required etc ..