Each poll is given a code upon creation. Whether you are displaying your poll within a presentation or as a webpage, you will then give students the code when you want them to begin voting. If students are using their phones, they will text their responses to the code, or they can use Twitter to vote on their smart phones or computers. Students can also vote on the poll’s web page using an embedded voting widget, or on their smart phones using pollev.com. Poll Everywhere has a helpful tutorial here: http://www.polleverywhere.com/how-it-works