It's really simple to automatically add Skype for Business web conferencing to meetings scheduled with FreeBusy:
- Go to the Account page.
- Click on Add More Calendars & Integrations tab.
- Find Skype For Business and click Add.
Sign in with your Office 365 credentials and your Skype for Business account will be automatically linked to your FreeBusy account.
Then refer to this guide on how to select your default conferencing provider for meetings scheduled with FreeBusy.