I will address the aforementioned topics, dealing with both the physical processes involved and the general astrophysical context. Apart of assuming a background of knowledge in physics and astrophysics common to everybody who will attend the course, I will spend an effort in order to take into account as a broad audience as possible.
The major bibliographical source is: The Observation and Analysis of Stellar Photospheres, by David F. Gray (2008oasp.book.....G)
The aim of the first lesson is to give a clear picture of what a stellar model atmosphere is and how it is built. The main physical processes that will be discussed are radiative processes, stellar opacities, and the meaning of termodinamic equilibrium and its local version.
In the second lesson we will analyze more deeply the model atmosphere introduced in the first lesson, reviewing how the stellar parameters (effective temperature, surface gravity and metallicity) affect it. We will then focus on line formation and, finally, we will see how to obtain information on chemical content of a star from its spectrum.