You can short through the likes of commsec that have CFd products, or you can use a CFD provider like IG (I use this)
If you've never done it before, make sure you do a lot of reading about exposure and amplifying gains and losses. I would strongly recommend that if you think it's for you, use IGs demo account for 1-3 months first and test your strategies. Learn what they have in their DIY learning videos, and then dip the toe in. Many on here would tell you we spent thousands learning the hard way.
