How to develop a windows software which can share session and sent and receive audio

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C#

Windows

.NET

Win10

we are hoping to develop a software called distributed learning system.
The main features implemented in this software are:

1) Students can view the teachers desktop in presentation mode.
2) Voice of teacher can be heard by individual students (VoIP).
3) Teacher can moderate students communication in group discussion sessions.
4) Teacher can listen to voice of the students
5) Teaching session can be recorded.

i came to know that session sharing can be done by rdp protocol in windows. But i am not sure about how rdp works or how the session is sent and retrieved from a server. I am hoping to sent voice using voip and would like to know about the role of the server here too. How can i integrate both these protocols given the two separate servers. Are there any different protocols which may make this easier.

What I have tried:

i have tried rdp and voip protocols