I already visited their website, but I don't see how to do chapters, sections, subsections, etc. Should this be done in LaTeX or in Markdown (using #, ##, etc.)

I already visited their website, but I don't see how to do chapters, sections, subsections, etc. Should this be done in LaTeX or in Markdown (using #, ##, etc.) or pandoc specific? Would you have an example of document with chapters mixing Markdown and LaTex?