Multi user, one active, others wait.

I want to make a page using ASP.NET C#, which includes some controls and a video
player on it. The first user only can see and use the controls, the other logged
in users can only watch the video. Right after the first user logs out, the
second one will be able to see and use the controls automatically. 

Users will wait in a "lobby" while the active user is using the
system. when they are waiting in the lobby, they may chat each other. 

This is my homework and i do not have much time. Please i beg your help.