Here is the information on posting a poll from the FAQ tab at the top of the forum page:
Creating a poll is easy -- when you post a new
topic (or edit the first post of a topic, if you have permission) you
should see a Add Poll form below the main posting box. If you
cannot see this then you probably do not have rights to create polls.
You should enter a title for the poll and then at least two options --
to set an option type in the poll question and click the Add option
button. You can also set a time limit for the poll, 0 being an infinite
amount. There will be a limit to the number of options you can list,
which is set by the board administrator