This is your eepsite - simply edit the files under ./eepsite/docroot/ and they'll be reachable. The 'key' to your eepsite that you need to give to other people is shown on the I2PTunnel configuration configuration page).
If you have any standard java web applications (.war files) such as blojsom or SnipSnap, simply drop their .war file into ./eepsite/webapps/ and they'll be reachable at http://$yourEeepsite/warFileName/
You can also reach your eepsite locally through http://localhost:7658/. If you want to change the port number, edit the file ./eepsite/jetty.xml and update the I2PTunnel configuration accordingly.