Computer Basics · Files & Folders · Lesson 1 of 5

What Files & Folders Are

Meet files, folders and File Explorer, the app that keeps them tidy.

Files, folders and File Explorer

Everything you keep on a computer is stored as a file. A file is one saved thing, like a letter, a photo or a song.

A folder is a container that holds files. It works like a paper folder in a filing cabinet. A folder can even hold other folders.

To look at your files, you use File Explorer. File Explorer is the app that shows your files and folders. To open it, click the yellow folder icon on the taskbar. The taskbar is the strip along the bottom of the screen.

On the left side of File Explorer, you will see the main folders:

• Desktop: the things on your main screen.
• Documents: letters, lists and other work.
• Downloads: files you got from the internet.
• Pictures: photos and images.

Double-click a folder to open it. Click the Back arrow at the top left to go back. You can't break the computer by opening folders and looking around.

On a Mac, this app is called Finder. Its icon is a blue and white face in the Dock. The Dock is the row of app icons at the bottom of a Mac screen.

On the practice computer, open Pictures and open the photo Beach. Then go back, make a new folder called Trip, and move Beach into it.

File names and the letters after the dot

Every file has a name, like Beach or Shopping list. Pick names that tell you what is inside. A name like Taxes 2026 is much easier to find later than Document 1.

Many file names end with a dot and a few letters, like beach.jpg. This ending is called the extension. It tells the computer what kind of file it is, and which app should open it.

Here are a few you will see often:

• .jpg or .png: a photo or picture.
• .pdf: a document that looks the same on any computer, like a form or a manual.
• .docx: a document made in Microsoft Word.
• .mp3: a song or other sound.

Windows often hides these endings. Instead, you see a small picture next to the name. This small picture is called an icon, and it hints at the file type.

When you rename a file, change only the part before the dot. If you change the ending, the file may not open the right way. Windows will warn you if you try.

Folders don't have these endings. They just have a name and a folder icon.