Where can I find In-depth documentation for entering and processing write-offs in A/R?

I have already spent nearly a day going through the various overviews I can find in the implementation manuals (A/R, Financial, Contract Billing, etc.); however, all the info is just that - an overview.

What I really need are step-by-step instructions for

1) how does JDE define "write-off"?

2) is there any setup necessary before using this functionality (e.g. any AAIs? other tables? UDC values?)?

3) how to enter a write-off against contract in Contract Billing?

4) what is the downstream process of the write-off (e.g. how is it reflected in the Customer Ledger, G/L, etc.)?

We've been using JDE 9.1 with tolls 9.1.5 for several years now, but this is functionality we have not yet explored and I need a beginner's starting place for learning this.