If you do not have the full client version of Skype, but need to connect to a Skype for Business meeting (for the first time).
1. After you click on the meeting link, choose Install and join with Skype-web app.
2. Install the app by clicking on SkypeMeetingsApp.dmg
3. Go back to the webpage where the program was installed from and click on Join the Meeting. click on Allow in the next step.
4. Type in your name and then click on Join.
5. You should now be connected to the meeting.