SASKTRAN-DO is an implementation of the discrete ordinates technique within the SASKTRAN framework. To get a sense for what this looks like we would recommend starting with the quickstart guide, and then go straight into looking at some examples at See SASKTRAN-DO Examples.
SASKTRAN-DO can also be used as a pure “scattering code” where layer optical properties such as layer optical depth, layer single scattering albedo, and layer legendre coefficients are directly specified by the user. Generally this option is only recommended for advanced users working on specialized applications. Some convenience methods are implemented to aid in generation of these layer optical properties, but this is still an area of active development.