The easiest way to install a plugin in your OpenWGA system is to use the OpenWGA Plugin Store - available from OpenWGA 5.4 upwards.
Open the Admin Client and select "Plugins / Plugin Store". The admin client analyzes your currently installed plugins, then negotiates with the online plugin store backend what plugins can be updated and what new plugins are available.
Just click "update" or "install" to get the latest OpenWGA plugins while the store takes care of fulfilling all necessary dependencies.
Installing Plugins not found in the Plugin Store
If you need to install a plugin not contained in the Plugin Store you needs the plugin as file with extension .wgaplugin.
To install such a plugin open the OpenWGA Admin Client on the server you want the plugin to be installed to and switch to "Plugins / Plugin Management" in the Main Menu.
The right content panel shows all currently installed plugins.
Click on "Install new Plugin" in the toolbar of the content panel and upload the .wgaplugin file to the server.
After the plugin file upload is finished the panel will show the installation as pending change. If the display is like the image below and does not show missing dependencies you may just click on "perform changes" to complete the installation.
If the panel shows missing dependencies you might need to install additional dependency plugins to get your plugin working. The panel should identify the names of those plugins for you so you can retrieve them from your plugin distributor. You then may just upload them additionally via the "Install new Plugin" button like you did before. Once all dependency plugins are uploaded the panel should show no missing dependencies any more and you can click "Perform changes" to install all plugins at once.
Other types of missing dependencies, like a too low OpenWGA CMS or Java version, of course cannot be fixed that easy. In that case you will need to update your OpenWGA CMS server or your Java platform in order to install the plugin.