Gardar ***************************
First thing book an appointment here
*********************************************
Then you decide if you want express or regular (express you get it stamped on the day, regular it takes two working days)
Then on the day you going mfa, people will come to you and ask what you need translated
I also recommend Narra Hotel it's near the mfa building. (walking distance)
Since the mfa building is about 1 hour away central Bangkok (Sukhumvit) with train and traffic is chaos.