To switch you email on or off, use the 'Edit Grid Data' button in the top panel and set the 'Active' checkbox. Also change your Email Address if required.
On the bottom panels, use the 'Edit Grid Data' button there to choose the Screen and Watch List items to be included in your email. You can additionally choose to receive the items as CSV files.
Daily emails are sent out once per day in the evening. You can also receive an immediate adhoc Email by clicking 'Send Test Email Now'.