Model is a representation of the metadata structures(imported from the soure datawarehouse).
A model contains organized metadata objects(organizing depends on business needs).
After the completion of a model(obviously in a framework manager environment) it has to SUBMITTED to ReportNet server.
Package:
There enterts the object called Package.
A Package compresses(or includes) the DEVELOPED meta data definitions and publishes (forwards) it to ReportNet server.
Then the reportnet server moves it into a content store(repositiry) and now this repository acts as a source for report developers for generating various types of reports(list reports, CROSS tab reports ETC etc.)