Direct Debits (UK) - Would you share your manuals?

Hello everyone in UK orgs

We're about to start using DDs for our membership scheme and I was wondering if anyone had devised any good internal user manuals that might help us set up our processes? If you have and you're prepared to share, I'd be delighted to hear from you.

I'm currently working my way through our sponsor's user guide so we can work out our processes and schedules but if you've learned anything useful it would be great to have extra tips!

Thanks
Alison