This is done using the IK Product Manager ("IKPM") and is posted here just for info.
-- run the IKPM and log in
-- set the IKPM downloads folder if needed
-- select the Software tab
-- navigate to the Syntronik 2 software and click [Install]
-- respond to the installer's prompts / choices
-- when complete, Cancel the suggestion to install the sounds
-- in Explorer or Finder double-check that there is enough disk space for the download files AND for the installed library
-- switch to the Sounds tab in the IKPM
-- for the Syntronik 2 library, click "... More Options" then "Install to" and navigate to the desired destination folder (e.g. L:\IK Multimedia\Syntronik 2), create it if you need to
-- once selected the download starts straight away (So make sure that you get it right),
-- go grab a coffee, while the sounds files are copied to the destination folder
-- when complete, Register your Syntronik 2 Serial Number
Now you can run Syntronik 2:
-- it will start to build its cache DB
-- I Cancelled this and went to Settings / Library to check the library paths
-- the default path (C:/Users/Public/...) was listed
-- as I have Syntronik 1 installed the ST3 library path was listed too
-- all looked OK, so I clicked [Rescan All]
-- it looks like the scan scans the complete ST3 library looking for Syntronik 1 instruments, rather than just in the relevant folders (reported to Support)
-- so I went for another coffee
-- 10 minutes later the scan completed and I was in business.
Finally, I copied the IKPM downloads folder to a back-up disk and emptied the IKPM downloads folder.
I got a Firewall Alert on the standalone as it did not have a digital certificate (reported to Support).