Gestures are a critical component of most mobile platforms these days, and users expect the apps they use to support them. A gesture can be fairly elaborate (say, drawing a shape, or using multiple fingers) or simple (just pressing an item for a certain time), but it is necessary that you get used to the idea.
When working on the device using native code, gesture recognition is typically provided to us nearly for free. That is, the framework provided by the OS does the hard work of recognizing a gesture.
Unfortunately, with PhoneGap, we lose that for free part and have to implement our gestures on our own. That's where ui-gestures.js in the www/framework directory comes in. Go ahead and open it up so that we can walk through some of what it does.