How to complete a 337?

Can someone point me to a reference describing how to complete the
"Description of Work Accomplished" section of a 337? I have seen maybe
a dozen completed 337s and they appear to be all over the map!

What I'm trying to do is draft a planning document describing what and
how I'm going to do my repairs to my fuselage and show not that my IA
has approved the work, but has OKed my approach. The same wording
woujld appear in the 337 when the work is accomplished.

I'm having to do this because there are large time spans between when
my IA OKs my approach and when the work is done and when a 337 is
generated. I think it would be a good idea to document that my IA had
approved my approach. - Mike