Fiscal policies are the policies governments use to manage the economy that involve changing the amount of leakages or injections in the economy (basically just changing taxation rates and government spending)
Monetary policies are the policies that determine the size and rate of growth of money supply. It is the reserve bank of Australia changing the official cash rate by forcing the commercial banks to buy and sell Commonwealth government securities, which in turn changes interest rates. The main objective of this policy is to keep inflation between 2-3%