I'm going to write about two different ways to do this: one right in blogger (a little easier, but more unreliable) and my preferred method: Poll Daddy. Now... onto the tutorial!
You can download this tutorial as a PDF by clicking this picture!
Note: This tutorial is hosted on Google Drive. To save it from there, just open the file and click File > Download to save onto your computer!
Next week, I'll add another blogger tutorial: how to add a followers box to your blog. This really confused me when I first made my blog... and blogger has since changed their options so this might answer some of your questions about how to add it!