Temperature gradient in Ansys
 

This is the first time to perform thermal analysis in Ansys.
I want to make thermal gradient on solid 70 elements. For example, the temp. on the top of the elements is known to be 60 and the temp. on the bottom of the elements is 20.
To my knowledge, I'll apply boundary condition (Temp.) on the nodes at the top with constant value 60 and the same at the bottom with value 20. Is this correct?. If yes, how can I proceed? which load do I need to apply (heat flux, heat flow, ...) and what is the value that I need to use?