To open an existing Notepad file, you can follow these steps:

1. Locate the Notepad file: Navigate to the directory where the Notepad file is saved. By default, Notepad files have a ".txt" extension.
2. Double-click the file: Once you've found the file, double-click on it. This action should open the file in Notepad automatically.

If the file doesn't open in Notepad or if you want to specifically open it with Notepad, you can use the following alternative methods:

Option 1: Open the file from within Notepad

1. Launch Notepad: Open Notepad by searching for "Notepad" in the Start menu or by pressing the Windows key, typing "Notepad," and pressing Enter.
2. Open the file: Once Notepad is open, click on "File" in the menu bar and select "Open." Alternatively, you can press Ctrl+O on your keyboard.
3. Browse for the file: In the "Open" dialog box, navigate to the directory where the Notepad file is located.
4. Select the file: Click on the file you want to open, and then click on the "Open" button.

Option 2: Use the "Open With" feature

1. Locate the file: Find the Notepad file in its directory.
2. Right-click the file: Right-click on the file to open the context menu.
3. Select "Open With": From the context menu, hover over or click on the "Open With" option. This should reveal a submenu.
4. Choose Notepad: In the submenu, select "Notepad" or "Choose another app" if Notepad is not listed. If you choose "Choose another app," you may need to browse for Notepad in the list of available applications.

Once you've followed one of these methods, the existing Notepad file should open in the Notepad application, allowing you to view and edit its contents.