I would like to start with considering the time-dependent heat equation on a connected graph. To start, I will need to model it respect to time discretization. I mean I have to write something like: $$A T^{k+1} = B T^k + Cf^k$$ where the initial time is given and the time step is assumed to be fixed. First, I have to determine the matrix A, B, and C and write down in what form they will be.
Would you please let me know if you know some references or have some comments on this topic?
Try this document
PDE Approaches to Graph Analysis (Justin Solomon, Stanford)