Honestly, the first few polls I made I also had to stop and think about this. In the end I just experimented(admin privilige). What could help is making a Topic that is full of templates. However, the side effect is that many users will edit the templates and get into deeper trouble.
My recommendation would be to have a topic in your site with a title like “How to make a poll in Discourse”. In this topic use screenshots/gifs of where you demonstrate how to make different types of polls, and which settings to use.