Bro, I'm doing edexcel igcse. Basically expansionary monetary policy is changing money supply and interests to achieve macroeconomic objectives. If a country wants to increase employment, Eco growth , they will most likely use expansionary monetary policy where they reduce interest rates. This makes it cheaper to borrow so more consumers do so (also discourages people to save money in banks, as they get less back) , and with the money they spend on goods and services, this increase consumption leads to increase Aggregate Demand, and therefore economic growth. Also employment increases due to derived demand for labor (firms need more workers to cope with the increase in demand). However if a government wants to control inflation they wud probably use contractionary monetary policy- increasing interest rates meaning people are encouraged to save, and makes it more expensive to borrow, so Aggregate demand falls, and thus so does price levels. So it depends on what specific(s) macroeconomic objective the gov wants to achieve, because with each policy it is impossible to achieve them all.