@rher Number them from 1 to 8 in order of your preference. Failure to do so will result in your vote being put in the bin. Even if you put the major parties 7 and 8 and all the minor parties above them, at some point in the counting the minors will be knocked out and your vote will go to whichever of the majors you hate less.

If you refuse to submit to this humiliation ritual you'll be fined.