To lock the car you have to touch the door handle (either the LF or RF). You touch the rear of the handle for about a second and it'll lock the car.
I think in the owner's manual they say to use the palm of your hand to lock it. There is also a picture in the manual of where to put your hand.
To unlock the doors your hand has to be around the handle. You don't have to pull it, just have your hand around it. (again just the LF or RF)
Also to open the trunk when the car is locked just have the fob with you and press the switch just below the VW emblem, near the backup camera and it'll open. When you close the trunk the car will beep.