At times it can be helpful to work from a reference image. To add one in Fusion 360 click the "Insert" icon in the toolbar. In the menu that appears, click the button that says "Insert from my computer..." and then the plane on which you would like to view your reference image. Once you have positioned your image, press OK.

A new dropdown menu will add a new section called "Canvases." You can toggle the visibility of your reference image as well as delete it in this menu.