If it's the same as my 197 card then then are credit card size legth and width, but are much thicker.
The car only unlocks when you put your hand behind the door handle. There is a sensor on the body and another on the handle itself and when the wireless contact between the 2 becomes broken (ie, with your hand) the car opens. The system works really well as it only works when you are right by the car. If you are more than a couple of feet away it doesn't work. Then to lock the car you press the button on the handle. Once for normal lock or twice within 3 seconds to deadlock. You can check it has locked within a further 3 seconds by pulling the handle. After 3 seconds the car will just unlock again by putting your hand behined the handle.
You can only operate the driver and passenger doors when standing by either (so if you stand by the drivers door the passenger can unlock their door or vice versa) but the boot cannot be opened unless you are standing by it, or the car is completely unlocked.
I hope this helps,