So I have an AGXD board that I am connecting to a Dynamixel Servo to move the wheels for kaya

I was wondering what is the difference between the ISSAC SDK and the Message Api. Which one should I be using in this situation. I have set up the ISSAC SDK already. If I have to use the Message Api are there any sample files that I can use with the Dynamixel servo to move the wheels and if so how do I go about running them? Thanks so much!