genSub tutorial needed

[Dennis Nicklaus <nicklaus@fnal.gov>]

Can someone please give me a step-by-step explanation of how to use
the genSub records?  I've read the record reference manual entry for 
them and
I still don't get it.
Here's what I want to do: 
1. Have a function which would create two arrays, I and Q,  of N points 
each, using several input parameters (values of other PVs) whenever any 
of the other PVs is set.
2. Copy these 2 arrays out to two separate VME memory address locations
(I'm copying an array to an array of addresses, not 
each-element-in-the-array-to-the-same-address as in a FIFO).
3. Process other records as with an FLNK link.

This sounds simple enough, but it is beyond my meager EPICS knowledge.
Thanks!
Dennis