1). Go to the LightWidget website and enter the settings that you see in the image below. Be sure to use your own Instagram name. Of course, you can adjust the settings to your liking.
2). Click on Preview and then Get Code and copy the provided code.
3). In your wp-admin, go to Appearance > Widgets and add a Text box from your Available Widgets to the Full Width Footer Widget. Finally, paste the code you copied into the Text box, and save your changes.