Hello. Sorry, I'm a new Mac user and have used a PC all my life so I'm trying to learn here. When I open Finder I see "Macintosh HD" listed under "Devices." Then I see "Desktop", "my computer name", "Applications" & "Documents" all listed under "Places." Can someone explain each of these briefly and how they should be utilized? Where should I save a standard document? Say I download an app...where is it installed? Where are photos saved when imported into iPhoto? Thanks in advance.