It's preinstalled / enabled via the license key. The array will reclaim internal data automatically but for live file systems you will need to signal to the array what has been deleted as in the PPT I linked in my previouus response. The way to do this varies by operating system, Windows prior to 2012 required a manual script to be run, VMware has it's own unmap etc, if your using the 2 together you may have to use one after the other.
See this whitepaper, page 27 onwards and appendix A and B.
http://www8.hp.com/h20195/v2/GetDocumen ... A3-8987ENWThis subject has been covered extensively on the forums so I'd do a search if you have further questions around space reclamation as it's likely been answered before..