Ax 2012 SSRS Reporting concepts

The picture is self explanatory and just to brief things up:
Basically a Report Model can contain Reports, Layout Templates, Table Style templates, Report Database etc..
And nodes which we can find under Report/Report Model are Datasets, Desgin, Parameters, Data methods and Images.
In Ax terms, a Datasets can be said to be a data source and collection of fields from data source.
And basically an Ax Query, SQL Data, OLAP data (cube) and a Data method can act as a Data source for a report
Design node of a Report/Report model will contain three major parts, namely, Header, Body and Footer.
And the Desgins can be of two types, namely Auto Design and Precision design.
Dynamics Ax will take of the conversion form the Designs to RDL files, the format in which reports are stored in the SQL Database.

Internal links:
SSRS Ax 2012: How to create a simple SSRS report - Link
SSRS Ax 2012: How to design reports with built-in templates - Link