From what I can tell, that pdf file is simply the same instruction doco as from Lynxmotion
for the SSC32. For that matter, I see nothing in the pictures on the the bizoner site
that looks like anything related to BT, so I think all in all they are being extremely
(1) no manual on the site.
(2) nothing whatsoever on the bd having to do with Arduino, per se.
(3) nothing about BT that I can see.
That's 3-strikes against. I don't think I would buy anything from those guys, myself.
OTOH, you should contact them directly to get the docos for the bd, and find out
what their definition of BT is.
As regards Nunchuck, you should power it off the 3.3V on the Arduino bd.
Also, I'm not 100% sure of this, but from the 328P d/s, it looks like the 2-wire I/F on
the chip is open-collector [open-drain] outputs, so you should be able to I/F to the
Nunchuck ok if you use external pullups to 3.3V - I think.