question about installing a plugin in Eclipse

[zpzpzp]

Hi

I downloaded a Eclipse plugin (a zip file) from this following site:
http://sourceforge.net/projects/shelled/
In the zip file there are:
/features
/plugins
site.xml
content.jar
artifacts.jar

However I do not know how to install this plugin in Eclipse.

Do I simply copy /features and /plugins to the corresponding directories in Eclipse? If so, what should I do with the rest 3 files?

Could someone please advise?

Thanks a lot.

Paul