They don't update their literature for most new releases and it could have been removed. It's been a while but it used to install in several parts, the client, server piece and "stream media server". Ensure you installed all of them. Later versions have full and lite versions, ensure you installed the full.
Make sure you've enabled "stream media server" as this video instructs: https://youtu.be/Bz2soZMxIBU
If all that fails go to earlier versions that have this functionality. I know iVMS-4200(v2.5.0.5) had a Lite and Full Version. You may even have to go back further to v2.4.1.3
Let me know if neither of these have it and I'll dig up an older version and put it up on Dropbox.