We recommend that you use the SumoMe list builder. It's fantastic and best of all it's free. You can read more about SumoMe at: http://www.sumome.com

First you'll want to install the Free SumoMe app:

The app will automatically add the appropriate SumoMe code to your storefront.

Now you need to configure the SumoMe app by visiting your store front

On your store front you should see a SumoMe tab you can click

Next you'll need to log in or create a SumoMe account

Next you can launch the Sumo store and install your apps:

Then install the list builder:

Don't forget to customize the design to match your store front!