Unfortunately, the answer is complicated. Chaturbate advises you to open an additional page from where you could broadcast yourself while you will hear and watch the webcam model on the first web page.
This logic requires you to broadcast yourself like a regular cam model. However, you can set a password to your chat room so that only the cam model can enter your password-protected chat room. A tutorial made by bestwebcamsites.com explains how to do cam2cam on chaturbate.
We tried it but we didn’t succeed. We have been automatically kicked out from the chat room of the camgirl because the website thought we entered the chat room twice.
Note that stripchat is similar to chaturbate without the pitfalls. It is possible to enter public chat rooms, watch a live sex show for free, assess the quality of the camgirl and then decide to go for a private chat in a cam2cam mode. On stripchat, all private chats are exclusive one-to-one webcam chats. You can decide either to text chat or to have a 2-way audio and video webcam chat with a cam model.
If it is too complicated for you to set up a cam2cam chat on Chaturbate, I would suggest you to try camgirl chat websites that include a cam2cam feature by default like Stripchat.com . Stripchat.com is similar to chaturbate but it features cam2cam.