A monthly report is simply an addition of all the Z Reports you've made during the month. You cannot do a monthly report directly in the cash register, this must be done in Backoffice.
Log in and click Reports in the top menu.
Choose Your Reports.
Z Report is already chosen in the option to the left. Click Start Date and choose the date to start the report from. When you click the date you will automatically jump to choosing End Date. Click Show Report when ready.
The system will summarize the months Z Reports into one large monthly report. You may now print it, or download an SIE file if you have configured a chart of accounts.