Youre missing a few things, you need re-read the first page of the manual: :excl:
http://www.ucapps.de/midibox_sid_manual_hw.html
have a look of the PDFs, (the optimized c64 psu circuit diagram in particular, you will need to buy components for this.)
These will show you all the wiring required.
Everything is explained on there, if youre ordering from SmashTV be sure to buy
some Ribbon cable, and a female IDC connector in shop:
,
for connecting the Core module to the LCD module.
You can tear off individual wires from the cable too.
If you rather not solder wires to the SIL pins (as shown on the bottom of the Core module page),
and prefer them to be detachable,
buy some SIL crimps and headers like these from smash:
Smash also has a crimping guide on his site in the info page,
you will need a crimping tool for this, ask smash if he has one in stock,
he *may* have one left.