You can install the plugin in your Jaspersoft Studio 5.6.0 or later versions.
The plugin doesn't currently work with the 6.0 series of the Jaspersoft Studio.
To add this plugin first add as an update site the following address:
https://github.com/WedjaaOpen/ElasticJasperSite/raw/master/
Then you should be able to select and install the plugin.
Refer to the ElasticJasper repository for the source of this plugin.