Having trouble in creating conference. i need to achieve where when the agent is having conversation with a client the agent can add another person in the room. I research some documentation but it's just transferring the caller to the conference and the conference creator is not in the conference.
Twilio developer evangelist here.
The best thing to look at will be this blog post on warm transfers using Twilio. It is in Python, but the theory is the same.
The basic idea is that you get the first two people into a <Conference> first. Then you can make a new call to the third person you want to bring in and drop them into the same conference which adds them to the call.
Let me know if that helps at all.