update: Name Manager documentation page

docs/src/web-application/name-manager.md

@@ -6,7 +6,20 @@ lang: en-US
 
 # Name Manager
 
-::: warning
-**Note:** This draft page is under construction 🚧
-:::
+The **Name Manager** makes working with specific cells or ranges easier by letting you assign custom names and set their scope.
 
+## How to Use It
+
+1. Click the **Named Ranges** button in the toolbar.
+   - A dialog will open.
+2. Click **Add New**.
+3. Input a name to identify the range.
+4. Set the scope:
+   - **Global**: Applies to the entire workbook.
+   - **Sheet-specific**: Applies only to the selected sheet.
+5. Click the check icon to save your changes.
+
+## Managing Named Ranges
+
+- Use **Edit** to modify name, range, or scope.
+- Use **Delete** to remove ranges when they’re no longer needed.