You cannot set up multi polls in a thread,just one.The only way you can get the poll change is if the mod of the forum is willing too.
how to set up polls is easy,once you ask the question,for example what color is better blue or red.
then you scroll all the way down click yes,post al poll with this thread,and then select how many posbilities to vote for,then add them in and click post thread.
and im pretty sure theres a Sticky on how to do this in the other voting polls forum.
So go check that out also.