Introduction
With Skype for Business signed in, click the call forwarding button at bottom. Click Simultaneously Ring and select the desired contact or number.
Instructions
1) From the Skype for Business window, click on the "call forwarding" button at the bottom.
2) Point to Simultaneously Ring and choose the person or phone number of your choice.
Outcome
Incoming calls to your Skype for Business number will ring at the location you specified as well as on any of your own devices where you are signed in to Skype for Business.