This video shows how the Xink Outlook app for Windows installation Works when you install it unattended. You need to install the client app if you want to see the email signatures in Outlook and deploy them to Outlook from Xink.
You request an msi package from Xink Admin which you can use to add to your deployment tool or GPO.
If you only want to use Xink to distribute email signatures through Office 365 and Google Apps, then you might not need to install the Xink Outlook app. You only need to install this app if you want to be able to see the email signature while composing an email in Outlook.