Convection Heat transfer coefficient (hcoeff) Problem

Hi, ALL

I am new in COMSOL, and i want to know what are the steps to set up this type of complex correlation for (hcoeff);

h= Nu*k/L; Nu=f(Ra,Pr), manually?

In the following link, there is a paper that tell us we could make this manually but not tell us how (thermos_laminar_hcoeff.pdf / Page 6):

www.comsol.com/showroom/documentation/model/1448/

Any ideas.
Thanks