Polls can be uploaded prior to the event by your organizer. When you’re ready to launch a poll, you will see them on your right sidebar. You can only launch one poll at a time. To open the poll, click "Open" on the right sidebar.
To show the poll on screen with you -- so attendees can see results come in in "real time" click "publish." Note: you do not have to publish the poll in order for attendees to vote. They will still have to go to the right sidebar in order to cast their vote. When you are done showing the results on screen, just click "End Presenting" on the bottom right corner of the card (on screen) or "Unpublish" on the right sidebar.
Once you are done accepting submissions, click "Close" on the right sidebar. This will stop voting and hide the results from the attendees.