Bc2000 (for the BCF2000 & BCR2000)

I looked all over the internet, the manual doest not provide
sufficient information for a newbie like me. So im kinda glad i found
this group. I was using a single BCR2000 and a BCF2000 both as solo
devices so far, few days back i got another BCF2000 and now i want to
merge the two BCF's. I did every thing according to the manual, setup
all the midi in and outs. It doesnt seem to work. I dont get it when
the manual says set the UNIT 2 to MODE 4. whats mode 4 ? Some help
would be really apreciated. thanks guys