Office Timeline does not support PowerPoint for Mac.
Office Timeline is unable to install on Mac OS’s and does not work with PowerPoint for the Mac. It can be deployed on a Mac virtual machine using desktop virtualization solutions like Parallels or Bootcamp to run Windows, however, this is not a tested scenario.
Mac users should request access to the upcoming cloud version of Office Timeline by submitting a support ticket titled "Pincello Preview".
See Windows PC System Requirements here: http://support.officetimeline.com/hc/en-us/articles/201950763-System-requirements-for-Office-Timeline