Would you please elaborate about the Sidebar? I get a little confused with what's what. At least I know what the Dock is.
When you open a Finder window -- any window showing say the contents of a folder on the computer, on the left hand side, there is a vertical bar with links to the Applications folder, your Home Folder, Music, Movies, etc. That's the Sidebar. See the left side of the pic below, where the highlighted "Student" folder is (yes, I know, I hotlinked, IM TO STUPID FOR TeH INTERNET!!!!
).
Also note that in addition to ctrl-clicking or right-clicking the folder icon on the dock to expand it, you can just click the left mouse button and hold it.