Visit the email list home page.
In the upper right corner, click the person icon with the down arrow in it. You'll see options like this:
Click the "Membership and email settings" option as shown above. You'll see a pop-up window like this:
In the window, you can change your email delivery preference to one of the following:
- Don't send email updates
- Send daily summaries
- Send combined updates
- Notify me for every new message
Most users will choose either "every new message" (usually the default) or the "daily summaries" option. The "don't send" option is appropriate if you never want emails and you'll just view all messages in the Google Groups web page.