A small or shallow depth of field (DoF) means a smaller range of focus. The closer the focused distance, the less DOF you get or in more technical terms: the wider the aperture (lower f stop number), the shallower the DoF.
A shallow DoF means you can deliberately blur out details in either the background or foreground of the scene, allowing you to draw the viewer’s attention to one particular subject or part of your scene.
For this Challenge, practice using a shallow depth of field in your photograph's to create a sense of intimacy around the focal point of your shot.
Get creative & Good luck!