Well, when you create a new thread, you have the usual space to write title and description for your thread and below that, you'll have an Aditional Options Panel with several extra options for your thread.
Just check the "Yes, post a poll with this thread and fill the number of options space with... you know what lol.
When you've created the thread, vBulleting will ask you to fill other things like options and voting preferences, basically, it's pretty much that :D.