Just got a Iphone 4. To connect to my home wi-fi I put in the password but I don't see any button to "connect" or "enter". There is "join" button but nothing happens when I touch that.

Just got a I Phone 4. I typed my wifi password to connect to my wifi but don't see a "connect" button or "enter". I tried "join" but it did nothing? How do I connect to my wi-fi so I don't use cell minutes when at home? Also, How do I know for sure by looking at the phone if the phone is utilizing the wi-fi versus cellular data minutes?