ZOOM iOS SDK Screen Share

follow the document, I add broadcast and implement onClickShareScreen. I only see the Screen button, there is no anything shown out after click ‘Screen’. I am sure the root cause is I never implement valuable code in onClickShareScreen function.
Anyone has a sample code for onClickShareScreen ?

/*!
@brief Designated for user click share screen item.
@param parentVC parent viewcontroller to present Share Screen Usage Guide View.
@waring App would present Share Screen Usage Guide here.
*/