Well, one thing you have to learn is that their are two flavors of JD Edwards - World, and EnterpriseOne. You have posted this to the World forum. There is a separate forum for EnterpriseOne (keep scrolling down past the World forum to find it). Technically World and EnterpriseOne are quite different. So it is important that you deal with the right product. World runs only on IBM AS/400, or iSeries, or Series I (IBM keeps changing the name of the computer) hardware, whereas EnterpriseOne can run on various kinds of hardware. World also uses only the RPG programming language, only with the IBM OS/400 propietary CL progamming language.
Having said all that, the place to start may be on the Oracle technology web site. Go to the Database/Documentation section and scroll down to find the JD Edwards Enterprise One area. That will give you access to the EnterpriseOne manuals. As with any major ERP system, the best way to learn is to attend the formal training classes. Otherwise trying to learn on your own is pretty tough, same as with Oracle EBS. Obviously if you run into a very specific issue, you can post a thread on that. But as for trying to find stuff to study/read, that is going to be tough.