Take a picture of the problem. It’d be much more helpful. Sounds like a heat transfer course. I am not sure whether it is external flow over a plate surface or just natural convection is occurring. You should have some equation listed in your book dT/dy. You need to integrate that equation with respect to y to find your temperature distribution as a function of y or x or in whichever direction you are considering. The 220°C sounds like a boundary condition where T(0)=220°C. Not entirely sure what else I could give you since there is not much to go off of. Thought I’d try.