Casio CZ/ VZ/ FZ - Pro Series

Just picked up a mint cz-5000 @ yard sale for $35.  It has all 
manuals. But I need a cartridge to store some sounds.  Anyone know 
where I can get one?  It's quite a daunting machine & I'm a guitar 
player not a keyboardist.  I'm getting the hang of creating sounds (I 
can see this is really an incredible & powerful vintage synth unit) 
but I'd appreciate anyone who may have a more simplified way to 
explain to me how to alter the parameters to create various sounds, 
i.e. are there certain parameters/steps in the DCO DCF, etc. that 
clearly have more dominant effects on the output sound?  Thanks.

bluz