feat(usage): basic usage guide

contents/user-usage.tex

@@ -12,3 +12,32 @@
 
 \chapter{Usage}
 \label{chap:user:usage}
+
+\rotare is fully controlled by a single input file, where the user specifies the
+simulation parameters, the rotor geometry, the flow conditions, etc. See
+Chapter~\ref{chap:user:input} for details about this configuration file. In
+theory this is the only place that requires user's attention.
+
+First of all, make sure you are in the \directory{rotare/src/} directory, or
+that it is in \matlab's Path.
+
+\rotare can be called directly with a configuration file or without one. If no
+configuration file is provided, the user will be prompted to select a
+configuration file manually. This feature allows the user to call \rotare from
+an other script and simplifies the interfacing between \rotare and other
+scripts.
+\bigskip
+
+\begin{lstlisting}[language=matlab]
+% Manual selection of input file
+rotare
+% With a specific config file
+rotare('configs/my_config.m')
+\end{lstlisting}
+
+\rotare comes with a few test configs (a template file and some reproduction of
+experimental results). You can verify that everything is working as intended by
+running any of these files:
+\begin{lstlisting}[language=matlab]
+rotare('configs/template.m')
+\end{lstlisting}