..bit embarrassed to ask - yet I just don't know shit about electrics, and searching youTube etc just gives me solutions for much more complex scenarios, so here goes:
I have very old / standard (German) wiring in my flat.
There is a room that has one switch by the door, this switches on or off the only ceiling light that is there - as on the left in my drawing there are two little cables (blue and brown-reddish) going into a lustre terminal (?) - and out go two, joining together in one cable that goes to a standard (E27) bulb fitting.
What I want is: three cables, three bulb fittings, all three shall light when I use the switch.
How would I do this?