Hi ga2peio,
welcome to the world of vrops.
I'll try to give you a few tips:
1) create a view ( I'll leave you an image )
IN DATA TAB
- Subject: Virtual Machine
- Favorites/Configuration/Creation Date (Days)
-- Set as Units DAYS, Descending Orders, Timesstamps, Relative Timestamps.
IN TIME SETTING TAB
- Basic
-- Absoulte Data Range, Prior 1 Months.
FILTER TAB
- Properties, Configuration|Creation Date, Timestamp, is , In the last 30 days.
SUMMARY TAB
skip.
DONE.
Now Go on report, Schedule and select the view you have created.
Please let me know if there is some doubt.
Have a good day.