Ffrank- I thought you only put your finger/thumb there to unlock the car? Does it also lock it?
I would draw a pic, but I'm at a customers

I'm not sure how good the manual is for this, but to unlock you put you hand (4 fingers) insider the handle, as if you are going to pull on the handle (sensor is on the right inside the handle.)
To lock, yes - you briefly touch the little dimple on the left outside of the handle.
I like to hang my jacket in the back seat so I just stick my hand in the front handle to unlock then open the rear door, works quite well as before I got the car I was imagining I would have to physically open the front door first.
The boot just unlocks when you open it, and locks itself when you close it.