1. Have an image. You need an image to add as your background!
2. In the Blender 3D View, press ‘N’ to pull up the right toolbar.
3. Then, scroll down on the bar until you see a header that says “Background Images”
4. Check the box beside the header, open the header, and press ‘Add Image’. Then click ‘Open’ and open your image.
5. Now you have the image loaded, to see it press Numpad 1, 3, or 7. Also press ‘Numpad 5’ to toggle Orthographic view.
6. Some other options for the background image is size, view, location, and opacity.
An optional way to import background images is to just drag and drop the picture right onto the background of your 3D viewport!