Dock is the Windows Start Bar equivalent in MacOS. However if a program is installed on your MacBook, unlike Windows, you’ll need to explicitly add it to the Dock.
To add an icon to Dock: Just click on the Finder icon in Dock, 
, locate the installed program and drag/drop the icon to Dock. This can be done from the Desktop as well.
To remove an icon from Dock: just drag it away from the Dock onto the desktop; the icon will disappear in a poof of smoke 
Dashboard is Windows Sidebar equivalent in MacOS – it is used for hosting widgets and activated by the default keyboard shortcut of F12.
| To add widgets to Dashboard: Some common widgets are included with the OS itself and can be enabled by clicking on the + button in left-bottom corner of the screen when Dashboard is visible. More widgets can be downloaded from here or by clicking on +, “Manage Widgets…” and “More Widgets…”. |  |
To remove widgets from Dashboard: Deleting a widget requires you to hold the Option key over a widget which enables a X in the left-top corner of the widget. Just click on the X and the widget will disappear.
A complete archive of all Mac OS X tips on this blog are available here.
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