I’ve followed the directions to add the event calendar to the menu. The problem is that I’m not seeing any of the options described in the video in the admin section of my site. I’m using the latest install of WordPress for Multisites.
You can just create a custom link but try clicking on Screen Options in the upper right and checking Events, Venues, Organizers and Event Categories. Once you check those boxes you should more comprehensive options for adding event related items to your menu(s).
I hope that helps but let me know if you need anything else with this.