How to manually install software/plugin to Eclipse IDE?

I have downloaded a RAR file from the following location, to be (manually) installed to Eclipse (Helios). How can I perform the manual installation?

http://sourceforge.net/projects/eclipsesql/files/SQL%20Explorer%20RCP%20%28exc%20JRE%29/3.6.1/sqlexplorer_rcp-3.6.1.macosx.cocoa.x86.tgz/download