It is simple and self-explanatory, so long you know what you want to place in the poll for the users to vote on. But if there still be some uncertainty, here in a brief explanation on how it goes.

In the above image:
1)
Subject: This is the topic of your post, which covers both the poll and the discussion that will come underneath.
2)
Message Icon: You can leave it as Standard or your choice to change, as it has no much thing to do with the post you are making, except you just want to cause little attraction, as almost 90% post made in the forum are all standard. For polls, it automatically changes by itself.
3)
Question: This is where the poll question comes in, which is mostly seen at the top of the thread before your discussion under.
4)
Option 1 - 5: These are the spaces where you are to give your options to be selected.
5)
Add Option: This is only used if the available options (1-5) is not enough for your poll.
6)
Maximum Votes per user: How many times do you want a user to vote in the poll created? This all depends on the poll creator, as it can be more than one, but one has been set as default.
7)
Run the poll for: This is how long you want this poll to last, it could be 1, 2, 3 weeks etc.
8)
Allow users to change vote: This is valid if you want users who has casted their votes to change it later on.
9)
Result Visibility: This part is interested in how you want the result of the vote to be displayed to the users, as it can be shown to anyone, someone who voted or after the poll has expired.
I hope this serves well.