The Skype for Business app is installed separately from the rest of the Office apps. If they are using Macs, point them to Set up Lync for Mac 2011 for Office 365. Point them to these instructions: Install Skype for Business. Step-by-step installation instructions: If you have a small or medium-sized business, we recommend that you simply ask your users to install the Skype for Business app on their PC. For most small and medium-sized businesses If your users aren't allowed to install software on their devices, you'll need to install the Skype for Business app for them. Or they will need to be part of a local group that can install apps on their PC or devices.
For users to install the Skype for Business app, they need to be local admins on their PC or device.
