The "Blink" sketch is fine if you only ever want your Arduino just to blink a light. But odds are good you want it to do some other things as well, like read a button, or run some other outputs.

The trick is to get rid of any long delay() statement, because during delay() the Arduino generally can't read inputs or change outputs. (There's an exception: a special thing called an interrupt can run even during a delay, but it's a bit tricky to implement and not recommended for a beginner.)