Hi Gena,
To add social icons to the footer of your emails just follow these steps:
1. Login to your control panel.
2. Visit your “Social Icons” tab.
3. Fill in the field for the social icon you want to add in the following format:
Facebook: Fill in your page URL by entering your page ID.
Twitter: Fill in your Twitter username.
Google +: fill in your Google + username.
YouTube: Fill in your the name of your channel or your YouTube user.
Pinterest: Fill in your Pinterest username.
4. Click on “Save”. Now your social icons will show in the footer of your thank you emails.
Also, if you added a link to your Facebook page a Facebook banner will show in your emails.

Let me know if you have any other questions.
-Tzipi