I assume you have passed your IVA, so congratulations on that
When I completed mine back in 2008 there was a useful guide on Totalkitcar but that has now been removed.
But, I did find this link that still seems to be relevant and may be a good starting point...
I guess the form may now have changed a bit to account for the latest options of paying by direct debt, etc.
I think Nigel and Mike have completed one more recently so may be able to answer any specific questions?