Oracle Retail SE is nothing but Oracle Retail ver 12.0.3. You just browse thorugh the Oracle Retail Library documents which are the standard docs (i.e. User Guide, Data Model, Operation Guide - part 1,2,3, Batchschedule etc).
Here's the link for ver 12.0.3:
Also you can download that from the edelivery site of Oracle:
The lastest news is that Oracle has released ver 13.0 with lots of new functionality. Recently at client location, we deployed ver 13 and tested the functionalities, but, wholesale and franchise functionality does not work truely. Oracle might come up with patches to resolve it hopefully.