Browse to the My Alerts section:
My MarketBeat menu header
Account Settings section
My Email and SMS Alerts tab
Navigate to the lower half of this page to see appropriate settings.
Bulk Actions dropdown will affect your entire watchlist.
Select the appropriate action in the dropdown and select the Perform Action button.
Earliest Alert Time will affect both email and SMS alerts.
Alert Types will enable/disable alerts of all the checked/unchecked type for your entire watchlist.
Make all your updates and then select the Save Preferences button below.