Ok, you select a timezone from the drop-down list (mouse click on it), and click "Apply" button, then all times will be updated.
Below is the prediction of the calendar. It might be wrong or right; but it tells you what to expect from logics.
Direction: the calendar predicts the direction of price starting from the shown date time. The up arrow means the price will go up from 9:30 AM afterward.
Volatility: tells you how fast the price will be moving at shown date time. If it's HIGH, you should expect very fast up and down movement. The higher the volatility, the more dangerous, but also more rewarding.
Future Chart: the price chart will be moving like this, starting from shown date time. At 9:30, GBPUSD will be moving up like that.
Take Profit: this is the potential profit you can make from selected event. It shows 144 pips, then you might want to set TP of your order around that.
You might want to play with past predictions, see them on charts.