Programs To Access System Resources

To navigate to a directory in Files, click (or double-click) on its icon in the right pane, the left pane, or the toolbar.
14.    Opening files
A file, in its simplest form, is data. Data can represent a text document, database information, or other media such as music or videos. To open a file, you can double-click on its icon. Ubuntu will try to find an appropriate application with which to open the selected file. In some cases, you may wish to open the file with a different application than the one Ubuntu selected.
To select an application, right-click the icon and select one of the Open With options.
15.    Creating new directories
To create a newdirectory from within the Files file manager, right-click in the blank area of the right pane and select NewDirectory from the popup menu (this action will also work on the desktop). Replace the default “Untitled Directory” title with your desired label (e.g., “Personal Finances”).You can also create a newdirectory by pressing Ctrl+Shift+N.
16.    Hidden Files and Directories
If you wish to hide certain directories or files, place a dot (.) in front of thename (e.g., “.Personal Finances”). In some cases, it is impossible to hide filesand directories without prefixing them with a dot.You can easily viewhidden files by clicking Viewoptions  ShowHiddenFiles or by pressing Ctrl+H. Hiding files with a dot (.) is not a securitymeasure—it is simply a way to help you organize your files.
17.    Copying and moving files and directories
You can cut, copy, and paste files or directories in the Files file manager by right- clicking on the item and selecting the corresponding button from the popup menu. You can also use the keyboard shortcuts Ctrl+X, Ctrl+C, and Ctrl+V to cut, copy, and paste files and directories, respectively.
18.    Customizing your desktop

Most customizations can be reached via the Session Indicator and then selecting System Settings to open the System Settings application window. TheDash, desktop appearance, themes, wallpapers, accessibility, and other configuration settings are available here. For more information see Session options.
20.    Appearance
The Look tab
In the Look tab, you can change the background, window theme, and Launcher icon size to further modify the look and feel of your desktop. To begin, open Appearance by either right-clicking on your background and selecting Change
Desktop    Background or selecting    Session    Indicator Appearance. Select the Look tab.
System    Settings 
Theme: The“Appearance” window will display the current selected background wallpaper and theme. Themes control the appearance of your windows, buttons, scroll bars, panels, icons, and other parts of the desktop.