E-set AHK

Greetings,

I have retrofitted a removable AHK and now wonder how best to connect the NSL and the return light. I don't really get smart from the instructions, on the one hand there was a so-called. Control-Link (is that the white control unit?), on the other hand, this could later rather be placed as if the two cables were to be moved up into the tailgate. Seems pretty cumbersome to me.

While browsing the forum, I also found the attached image - what kind of a relay does the red-yellow NSL cable seem to lead to? Mine doesn't have one.

Now again the real question: what is the method of choice to connect NSL and rear-view light?

Thank you!