How can I automatically generate a bill monthly that is emailed

Select your Meter Account.
Go to Edit->Meter Account.
Click on 'show more options' near the bottom of the screen.
There are two checkboxes that need to be set:
Send Bill as Pdf file attachment on notification when a New Bill is available
Attempt to run Bill Automatically, alternatively send Bill Error notification.
The cutoff is important: it is how long PNPSCADA will give for the meters to call in before running the bill.
You need to have enabled the relevant notifications for it to come through.