I bought this kit with wires on AliExpress.
There are many tutorials out there to disassemble the central console. Take a look at this one, for example.
You need to remove the central console, separate (destructively) its inner and outer parts, replace the plug ring with a transparent light guide for the LED and glue / solder the parts back.
Most guides (including the video above) describe how to connect rings to buttons light or a car cigarette lighter, but this is not the original way it should work. By default, wires run to the BCM module (09, J519). This connection allows you to control the light with a knob in the “Ambient lighting” menu of the MIB.
For cars with Xenon headlights, the wire goes to the 2nd pin of the T46B connector (in the middle) of the BCM module. Mass connects to the mass bolt 10cm left from there.
To access the BCM, you need to remove the hood lever and the plastic panel under the steering wheel:
UPDATE: I had coding issues at the moment of this retrofit. Everything was fixed a year ago in this article.