No tutorials. If you're trying to add something generic (like TimeZone) that OpenAudit doesn't currently audit you should code it yourself and submit the code. If you can't then you should submit a feature request with what you want audited fleshed out a bit.
Having said that: 10,000 ft view (and could be wrong):
Add code to audit script as appropriate.
Add field to database as appropriate
Add database upgrade code to admin.php controller upgrade function
Edit the appropriate model's process_* function
Edit views to display information
Edit report XML to display information
Decide you should have just made a feature request
Who knows how many changes Mark has made in the code since beta 9.2. It might be easiest to just make a request.