Fatal error activating Elastic Search

H there

Trying to activate Fantastic Elastic Search on out server delivered the below error.

Any suggestions in how to deal with this would be great

Plugin could not be activated because it triggered a fatal error.
You must set up the project dependencies, run the following commands: curl -sS https://getcomposer.org/installer | php php composer.phar install

Steve

https://wordpress.org/plugins/fantastic-elasticsearch/