What I learned: Small Aperture = High F-stop = Deep depth of field [everything is in focus]. Large Aperture = Low F-stop = Shallow depth of field [one thing is in focus, background/foreground/middle-ground; Depending how extreme] For my camera f/22 is the highest F-stop/Smallest aperture.

For the photo above is a low F-stop, f/4, and thus shows a shallow depth of field, making Claire's the only thing in focus.

In this photo, there is a high f-stop, f/10, and thus shows a deep depth of field, making the background more focused than before.