CDT
In order to do most EPICS development in Eclipse you need to have the C/C++ Development Tools (CDT) installed. These alone will go a long way toward helping you manage and develop EPICS Projects. There is more information in the C/C++ Setup topic including a picture of the APS front-end IOCs as managed in Eclipse and an IOC built for several platforms in Eclipse.
EPICS Base
You also need a version of EPICS base. There are many ways to accomplish this, as described in the EPICS Base topic.
CVS
Is often useful to manage EPICS projects, including EPICS Base and EPICS Extensions through CVS. There is more information on using CVS with EPICS here, and there is the tutorial on Using CVS to Check Out and Build Base.
EPICS IDE
The EPICS IDE plug-in is an additional plug-in that helps EPICS development by providing wizards to help make new projects, add to existing projects, and the like. It should be particularly useful to the new IOC developer and to the casual developer, one that has to manage IOCs but who does that in addition to other duties and who wants to get things up and running as fast and easily as possible.
The EPICS IDE has its own nature as well as C/C++ natures and thus has all of the properties of a C/C++ project, as well as additional ones appropriate to EPICS. It has perferences that can be set in Window | Preferences | EPICS IDE, and each project has properties that are set by the New Project Wizard or by you. It is available as an Eclipse Feature, so that it is easily installed, updated, and managed via the Eclipse Update Manager, available via Help | Software Updates in Eclipse.
MakeBaseApp
The New Project and New Application wizards in the EPICS IDE rely on MakeBaseApp, a Perl script that has come with EPICS base since at least 3.13.9beta4. There is more information about MakeBaseApp here.
Properties and Preferences
The EPICS IDE has preferences, set in Window | Preferences | EPICS IDE, and each project has properties, set by the New Project Wizard and by the user, typically by right-clicking the project and choosing Properties | EPICS Project. For an explanation of these properties see the New Project Wizard reference page.
Tutorials
Tutorials to help you get started are found here.