The OSCAL project maintains a variety of resources to learn and use OSCAL.
The concepts section contains detailed information about the organization of OSCAL models, processing specifications, and explanations of important primitives (i.e. identifiers) underlying OSCAL data elements.
The reference section contains the full details of all OSCAL models for development snapshots and all published releases, with visualizations of models in outline form, reference documentation for individual elements, and indices for the location of all elements across all models.
The downloads page has links and instructions to download releases and development snapshots of the OSCAL data models.
The examples page has links and information to examples of OSCAL content in the official NIST repositories.
The tools page has information about NIST's reference implementations of software and reusable libraries. Additionally, there are links to community-maintained lists of software and information about OSCAL-enabled tools.