Finite Volume Problem Heat flow

Here is the question I have -Write a MATLAB function that solves the problem of two-dimensional heat ow in a rectangular bar with no heat sources or sinks. The bar is two units long and one unit tall. The entire top boundary of the bar is xed at a normalized temperature of u = 1. Exactly one half of the bottom boundary is fixed at u = 0. The remainder of the boundary is insulated,with no heat flow in or out.Use finite difference, finite volume or finite elements to solve the problem. The function should take the total number of intervals m along one vertical column as input. All intervals will be square, meaning that the total number of discrete squares on the domain will be 2m^2. Write a script to call the function for m = 4, 8 and 16. The script will also plot the solution, by putting it into a rectangular matrix and using the MATLAB function contourf().

So basically I think I would like to use finite volumes unless there is something easier. My biggest is I don't really understand the whole process for finite volumes. I need help or at least pointed in th right direction. I've looked online and most of the explanations for finite volumes are just as confusing as how my prof teaches it.

Thanks for any help