To create a poll on the AdminSports app, just choose your team, go to the Messages tab, and tap "Compose SMS blast" at the bottom. You'll see a slider that says "Make this a poll". Simply tap to enable that feature, and your SMS message will listen for Y and N responses! These responses will be gathered in a pie graph that you can find along with your message in the Messages tab.
If you're having trouble making a poll, it may be because you already have a poll open. You can only have one poll open at a time—otherwise there'd be no way of knowing which poll someone's response goes to! If you have an open poll, it will be the only one with a green icon in your messages tab. Before making a new poll, be sure to close any open polls by going to that message and tapping the red "Close Poll" button at the top.