Not sure if the where's the 14 gears come from question was serious but basically if you're on the small ring at the front you have the seven gears on the back, then when you're on the large ring you have another seven gears; 14 in total.
Sorry to wheel out the pedantry, but for me calling this 14 speed is a bit misleading. You should avoid crossing the chain over by riding in the big chainring-big sprocket or small ring-small sprocket combinations.
It's something people new to cycling often do, but it wears the chain more quickly, and could potentially lead to breaking the chain.
Since it's probably not advisable to use the two big-big and small-small
combinations, it would be more accurate to call a bike like this a 10 speed really.
Like I say, sorry for the pedantry, but most people new to road cycling with
double rings (me included) make the mistake of crossing the chain over, but it's not a very good habit.