When you post a new thread and scroll down, you have the option to turn that thread into a poll. Polls may only exist in the polls forum, no other forum.

What you type in your thread is the content contained in the first post.

You tick you want to add a poll.

When you submit, you will be taken to an additional page to write the poll question and answers.

You fill in the blanks correctly and submit.

Your thread will then be submitted as normal with the addition of the poll above it.