When using the NetSupport Notify.msi file with an Active Directory Software Installation or SCCM the installation parameters will be added automatically when you add the MSI file.
If you need to add the MSI installation parameters manually at any point you would use the following: msiexec /i "NetSupport Notify.msi" /qn
Please be aware that you will also need to add the NSN.ini and a pre-configured Config.dat files to the folder the NetSupport Notify.msi file is located in to allow the installer to install the required Notify components and apply the connection details to the Notification Server.