Describes the site collection. The main responcibility is to describe and separate what needs to be deployed on the site collection level: - sandbox solutions - site features - security group and roles - fields - content types - user custom actions - anything else Construct your model using AddXXX() or AddHostXXX() syntax. If you have bunch of the 'plain' things to push, then use .AddDefinitionsFromStaticClassType() method. It is a good idea to avoid big model preferring small model per every reasonable operation. The final artifact separation and grouping is tootally up to you and your prpoject needs. Read more here - http://docs.subpointsolutions.com/spmeta2/models/