Add Clients To Conference Call In Sinch

I have implemented the Conference Call using Sinch and it is working perfectly. Now my requirement is I should be able to add clients to the conference call. According to the Sinch

Solution 1:

Yes you can use the ConferenceCallout in the restapi, there you can add users with conferenceid and userid https://www.sinch.com/docs/voice/rest/#Callouts