Oracle Warehouse Builder is the relational ETL tool.
Oracle discoverer is (or actually was) the reporting to query Oracle database. It has now been replaced by OBIEE (which used to be called Siebel Analytics in the past).
Oracle Analytic Workspace manager (also called AWM) is the tool that is used to create OLAP objects (i.e., Analytical workspace, dimensions, hierarchies, attributes, cubes and measures).
AWM is also a mapping tool where you can map relational views/tables to measures and dimensions, and then execute a load of those dimensions and measures.
You should just download AWM and the sample OLAP data from OTN website: http://www.oracle.com/technetwork/database/options/olap/