It sounds like you might be confusing Oracle Endeca Information Discovery with Endeca Commerce. These are two different products.
The E-Business products are all related to Endeca Commerce.
Oracle Endeca Information Discovery includes Oracle Endeca Server, Oracle Endeca Information Discovery Integrator, and Oracle Endeca Information Discovery Studio.
The documentation for these products includes the installation guides, which provide details on downloading the appropriate files. Links to the documentation for the full Oracle Endeca Information Discovery product is available at Oracle Endeca Information Discovery Documentation.
This is actually referring to the Endeca extensions for E-Business Suite (an Oracle ERP product suite). During my tenure at Oracle, I actually helped design the integration of the Endeca Information Discovery product for use within EBS. Branchbird has been blogging about the offering a bit too. http://branchbird.com/blog/category/e-business-suite/
That said, I was able to find everything I needed from the install directions (which are slightly updated from the version referenced in the post above). Can you please use these instructions and let me know if it still isn't clear what needs to be downloaded. You'll essentially install the OEID product (in a prep'ed integration form) by downloading the "quick install package" from edelivery. Additionally, you'll need to install patches to EBS to get it up to the right patch level. Then through a series of additional patches, you'll deploy the EBS changes required for the integraiton and patches specific to the "product" you're installing.
Again, all of these details are covered here.
Give this a look and let me know if it is still unclear.