Equation with variables into a line graph

In a "divide and conquer" strategy, which parts do you need help with? Here are the steps I would expect to see:

1) Enter equation coefficients.
2) Enter a column of temperatures covering the desired range. Note that to accurately show the phase changes, you will need two entries for those temperatures.
3) Enter a formula adjacent to the temperatures that computes enthalpy. I note that you are giving the equation for heat capacity Cp=(dH/dT)constantP, so you will need to take the antiderivative of your Cp function and compute a suitable "initial condition" so that H=0 at your desired reference condition.
4) Copy that formula (or formulas) down the enthalpy column.
5) Select T and H columns -> Insert Chart -> Scatter chart -> desired subtype (lines without markers??). Pay attention here so that you don't get a line chart. Make sure you get a scatter chart.
5a) If Excel gets the data series wrong (as it often does for me), then go into the Select Data dialog and fix Excel's mistakes.
6) Format chart as desired.

With the process broken down like that, where do you get stuck?