Here's how you can start using Siri on your iPhone 5.
1. Long press the Home button.
2. A menu will appear that says: What Can I Help You With?
3. Begin speaking into the iPhone 5.
4. Siri will attempt to answer your question or find the information you need.
5. A good, simple test question is: What time is it?
Siri is a helpful tool and works well on the iPhone 5. Have fun experimenting with Siri to see what she can do for you.