The microphone must know pum open-close. If you've never used it before, ask officials to lecture before the open-close the microphone? A simple story like this can affect confidence in the presentation.
Microphone button to know - closed. If you've never used before Before asking staff to describe it - turn off the microphone, however. Simple as this can affect the confidence in the presentation.
The microphone to pum - closed, if never used before Ask the officer before going to lecture on - off the microphone? Simple this affecting the confidence in the presentation