change currency

This sounds a bit dim, I am a brand new user, how do I change USD to AUD? I have followed other forum advice with great success, this product looks like a great solution for me. Thanks in advance.

Go to Admin area > Configuration > Location > Currencies. Then delete or unpublished all currencies except AUD.
P.S. And ensure that it's set as primary store currency and primary exchange rate currency.

i live in iran
but i can not see ريال


please help me

hi,
you should change the CUSTOM FORMATTING of currency to this :
ریال ###,###,###

and your prices will change to something like this for example :

ریال 233,500,000

We can add new currency in the admin panel

Configuration -> Currencies  

Then from the top-right corner you can add new currency.

You can find the detailed article here