The GA4GH Beacon specification is composed by two parts:
The Beacon Framework is the part that describes the overall structure of the API requests, responses, parameters, teh common components, etc. It may also be simply referred as the Framework.
The Beacon Model contains the data structure (schemas) for our biological data. It describes the set of concepts included in a Beacon version (e.g. Beacon v2), like individual or biosample, as well as the relationships between them. It may also be simply referred as the Model.
The Framework could be considered the syntax and the Model as the semantics.
Here is a explanatory video on Beacon framework and model, mostly aimed at implementers. Link to video from 01/07/2021
If you are a Beacon user you might be more interested in the Beacon model. You can also consult the user journey section. If you are a Beacon (future) implementer then you will be more interested in the Beacon framework. Make sure you take a look at the read me sections in both Github repos: Framework and Model, as well as the steps to deploy a Beacon.