The plugin is not hosted on the Wordpress repository at present, so you will have to download it off our package server.
Download the file from: http://spring-dvs.org/release/?package=wp-springnet
If you wish -- verify the integrity of the file by comparing the checksum against those provided on the download page.
Install and Activate
The following action can only be performed by Administrators on your Wordpress site.
Select Plugin > Add New
Select Upload Plugin
Browse to locate the Zip package and select Install Now (the version number will differ from the image above). It will provide a feedback screen on the installation process.
Either Activate Plugin or go to Plugins > Installed Plugins and click Activate