Setting up the Calculation

Setting up the Model Geometry

Configuration of global model grids (e.g. altitude), the global type of geometry (spherical, plane-parallel)

Specifying what you Want to Calculate

Setting up viewing directions for radiance output.

Choosing and Configuring Atmospheric Sources

Determining what source terms to include (e.g. multiple scatter, thermal sources)

Setting the Atmospheric State

Setting up atmospheric constituents like Rayleigh scattering and ozone absorption