To check out poll results, simply swipe up when viewing the story, and you'll see who voted and what they thought. The people who see your story can also view poll results; the vote tallies are refreshed in real time, so if they come back later to see it, they'll see new poll numbers. Additionally, Instagram announced a new alignment tool to help you place stickers. You can make sure your sticker is aligned correctly and also ensure that you aren't covering up an important part of your story.
The temporal nature of Instagram Stories (they're only viewable for 24 hours) makes pairing them with polls a smart idea. Just make sure you check back in before the story disappears to see the poll results!