Create a custom installation of Eclipse with Oracle Tools, by choosing the desired OEPE release and the required capabilities.
Launch Network Installer
These distributions include Eclipse with Oracle Tools already installed. Just download and unzip.
Developers with an existing Eclipse installation can use OEPE plugin repository to install the required Oracle Tools.
Mars M7: http://download.oracle.com/otn_software/oepe/18.104.22.168/mars/repository