I took a piece of aluminum sheet metal and did it myself, actually. Need some thin foam and a piece of upholstery material. What you can do differently is the distance between the switches by reviewing photographs to get the proportions right. On the picture you enclosed you see switches closer together than I have and what you have there is correct, I guess. I was thinking of a third switch when I did this, for DRL, but I ended up hooking them to rear window heater switch.
I am enclosing the picture of my car (Int).
You will need to shorten the carpet that goes on the bottom of the tray.
You also need to cut out a hole in the bottom of the tray if you do not have it.
I think any mechanic can do it.
Perhaps someone on this Forum has the exact dimensions. If not: you have information on the drawing "cut out 20x75mm long" and based on that you can determine other dimensions from the drawing. I would use flat headed screws (21 on your drawing, 17 on mine) as if they are too high, you see the raised carpet a bit. I am enclosing another drawing in English.