Yealink T48G-SKYPE FOR BUSINESS EDITION User Manual page 181

When the third party answers, three parties are now joined in the conference.
4.
Tap to invite a new party.
5.
Repeat the steps 3-4 to add more parties to the conference.
6.
Initiating a Conference Call from the Skype for Business Client
You can initiate a conference call on the Skype for Business client.
To initiate a Skype for Business conference call from the Skype for Business Client:
Place a call to the first party.
1.
Click
2.
new call to the Skype for Business conference.
to enter the number or name of the third party, and then click OK to invite a
Basic Call Features
167