Having discussed the preamble, we now discuss the document itself. As with most LaTeX documents, it starts with

\begin{document}

followed by a title page:

\title{\TeX~slide presentations}
\date{\today}
\author{JM Figueroa-O'Farrill\\[10pt]
        School of Mathematics\\[10pt]
        University of Edinburgh}
\maketitle

Everything is self-explanatory, except perhaps to note that the author will appear in yellow betraying the fact that it is typeset in display mode.

Next we discuss the slides themselves.