Is very easy, only you need a file with picture or drawing in format JPG.
With the model open in solidworks you must go to:
1.- "Scene, Lights and Cameras"
display the bottom "Scenes" then double click in "Background", this open a new dialogue "Edit Scene", then in Background Click in the bottom "Browse" and select the picture or drawing that you want and surprise the picture or drawing is in background of your model. Enjoy it. "LIKE" are welcome.
Only four step and ready.