What it is: The Finder is the most frequently used program on OS X because it lets you manage the files on your Macintosh.
The Finder icon always appears on the left of the Dock. Unlike other program icons on the Dock, you can’t remove or rearrange its position. That’s because the Finder is a crucial program that you’ll need to use to manage the files on your Macintosh.
With the Finder you can rename, move, delete, and copy files. You can also create folders to help you organize your different files.
One way to use the Finder is to open multiple Finder windows by clicking the File menu and choosing New Finder Window (or pressing Command+N). Having multiple Finder windows open can be handy because it lets you view the contents of two different folders so you can drag and drop a file from one Finder window to another.
However, if you don’t like showing multiple Finder windows all over your screen, you can also display tabs within a Finder window. Finder tabs work just like tabs in a browser. One tab represents the contents of one folder and another tab represents the contents of a second folder. By just clicking on the tabs, you can switch views within the Finder window.
To create additional tabs, you can choose File > New Tab or press Command+T. When you’re done with a tab, just move the mouse pointer over it and click on its close icon (an X) to make that tab go away.
By using tabs, you can minimize the number of Finder windows appearing on your screen and you can even drag and drop files from the Finder window over a tab. This is less intuitive than dragging and dropping a file from one Finder window to another, but it’s simpler with less clutter.
Once you’ve created two or more tabs, you can always break them into separate Finder windows by choosing the Windows > Move Tab to New Window command. If you have multiple Finder windows open, you can condense them all into a single Finder window with tabs by choosing the Window > Merge All Windows command.
You can use the Finder perfectly well without ever using tabs, but keep in mind that they’re available as a shortcut if you want to experiment with them. Tabs may not be crucial, but they can be convenient and anything that makes a computer easier to use should be welcome by everyone.