Thermal Stress Analysis

Hi Everyone,

 I am new to Abaqus. I am working on a research topic where in I need to study the transient thermal stresses, strains arised due to heating a body by thermal radiation.  From the user's manual I understood that I need to use "Sequentially coupled thermal-stress analysis" for my model.

 I want the sample surface to be heated at a specific rate (say 20 C/min). I am not able to figure out how to set this condition when using "surface radiation" heat transfer or may be at what rate should I change my ambient temperature for the body surface to get heated at the specific rate.

 Can anyone please help me in this regard? 

Thanks in advance.