when you're making a thread there'll be an option to include a poll under 'additional options' at the bottom. just tick the box, select how many options you want in the poll, and then after you submit the thread you will be able to make the poll.
from daylight...
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while you're creating a thread, there is an option at the bottom of the page to include a poll.

after you submit the thread, a window will appear allowing you to put in the poll question and the answer choices. you have several other options, such as multiple voting, public, closing date of the poll, etc.

if you want to add a poll to a thread you have made, just go to that thread.
at the bottom of the page, there will be "thread tools". adding a poll is one of the tools.

more info here: https://www.ultimate-guitar.com/forum/faq.php?faq=vb_read_and_post#faq_vb_poll_explain

good luck,
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