The smaller the aperture, the bigger the f/no. and yields deeper Depth of View(DOF). DOF determines how much of your images is in focus. The deeper the DOF, more of your image will be in focus (so call sharp). That's not all though. Distance of your subject and focal length of your lenses are also factors which determine DOF you get. Wide angle lenses will give you deeper DOF in general.
iirc kit lens does't have a focusing scale... u can try turning the focus ring all the way to the left or right and see which one gives you clear picture when taking picture of object very far away. that is infinitely focus.