How to connect my iphone to my Wi-Fi?

How do I connect my iphone to my Wi-Fi?

Added (1). It's got no SIM card yet, but it won't let connect to the internet is there another way to do it?

Pretty much the same way that you get anything to connect to Wi-Fi

1 Turn on the Wi-Fi on the phone
2 Select which Wi-Fi signal you wish to connect to
3 Enter, when asked, the Wi-Fi security key.