This is the power supply pinout picture
http://zxbyte.ru/pic/byte5_10.jpg "B" letters means "V".
!!! WARNING !!! This is PSU's side plug, not the socket on board, mirror it !!!
You can use just a piece of coax with stripped ends to connect it to the TV, good contact is not required, most of those HF modulators were so powerful that sometimes I was able to tune my TV to neighbour's ZX behind the wall
This particular modulator uses SECAM colour coding, some "western" TVs may show it B&W.
Having discretes vs ULA was cool - like having an "open source" ULA
I still have a schematic sheet of my first ZX somewhere at parents house.