All documentation are held within Veritas Support https://www.veritas.com/content/support/en_US.html
To find NSS documentation written in a specific language follow these steps.
On the left hand side of the screen is a number of headings with selectable lists.
Select the version of NetBackup your running from the ‘Product’ drop down list. Under the ‘Languages’ heading select the language you're looking for. From the ‘Document Type’ list select the document you're looking for.
Please note the installation guide is not translated and a good working knowledge of English is needed to run the installation process.