Go to Content- Footer Management. On clicking the Footer Management, Manage Footer page will come up which will have the preview of existing Footer on the website.
To Add a new column on the footer, click on the Add New column located on the right hand side of the page.
On clicking the Add New Column a small window will pop up. Fill in the details of the new column as per the requirements.
To edit footer, go to Content- Footer Management. The list of footers will appear on the screen. Click on edit icon of the footer to edit. Once clicked it will direct you to the footer page where the changes can be made.
Below are the screenshots of editing SITE LINKS footer:
