Download [1] a poster (select from the list below), print it, and post it up somewhere appropriate [2]. They're small PDF files, set up for A4 sized paper; you'll need something like “Adobe Acrobat Reader” to handle them. If you don't already have it, follow the “Get Adobe reader” link to the Adobe website, and there's another such link on their site to get the reader software (it's free).
Simply clicking on one of the above links may display those files in your browser, or it may download and save the file to your disk drive. It depend on how your browser works, and how it's configured to work. Either way will allow you to print the file, but if you wanted to print a file several times or keep it for future reference, it's probably more convenient to save the file to your drive. Precisely how you do that depends on how your browser works—there's many different ones, and they don't all work the same—so it's not possible to simply say how to do it for all of them, but many will pop up a menu to let you choose what to do when you click on links with the second mouse button; or for single button mice, if you hold down on the button for a longer period. Your web browser should have its own help files explaining how to do this.
It's permissable to place election posters on Stobie (power) poles and lighting poles, other places might require permission. Posters need removing shortly after the election. It's a federal offence to deface or remove posters, but don't risk arguing about this with strangers.