How do I add a background image?

Hey guys I’m doing another school project in blender, I’m having a problem adding a background image in blender. Here is what I did: "Press N, Scroll down to Background Image, Check the “Background image” Check box, Click add image, Then I’ve chosen my Image. But the image have not displayed at all. So what should I do?

Background Image only works for Orthographic display, not Perspective, so assuming you’re in perspective display press Numpad5 (or click on View -> View Persp/Ortho) to switch to Ortho display.
The background image will then appear in the view you selected (front/side/top/etc…)

also you can add an empty and change the type to image.