1. You will have to execute this script using Powershell. (Internally PowerCLI will come in picture ). 

2. You need to call appropriate function in the script (You can find at the end of the script there are some calls made .

     Ex.  Get-Datastore IX2ISCSI01(Pass you datastore name here) | Unmount-Datastore     (Remove the comments)

3. Follow below best practices before going forward.

Below are best practices to unmount datastore from vCenter.

Below checks should be considered.

-No VM resides on the datastore

-The datastore is not part of Datastore cluster

-The datastore is not managed by storage DRS

-SIOC is disabled for this datastore

-The datastore is not used for vSphere HA heartbeat.