To make an international call from one country to another country, simply select the country you're dialing from, then select the country you're dialing to, the dialing tool will display country code for to country to whom you want to call.
Now you need to dial area code and then phone number you'd like to call. Look at "International Calling Pattern" at the bottom of the page for your reference, showing complete pattern of how to make a call or dial an international phone number.