Our automated monthly reports do start on the 1st as a default. Once you set up an automated monthly report, the data will be gathered on the 1st, and the report will be sent out on the 2nd of each month.
First you will need to set the report date range which you can choose from various options in the report itself:
After the range is selected click on the automation icon where you will be able to choose the sending frequency and when to deliver those reports.
Then you can choose the frequency and delivered on options that suits you best!