You can achieve this by using a plugin called “Conditional Widgets”. Here are the steps to follow:
1. Install and activate the “Conditional Widgets” plugin.
2. Go to “Appearance” > “Widgets”.
3. Add a new Text widget to your sidebar or any other widget area you want to use.
4. Edit the content of the Text widget to include the text you want to display.
5. In the “Conditional Widgets” section below the widget, choose the “Show” option.
6. Click the “Add Condition” button.
7. Choose “Single Post” as the condition type.
8. Select the particular blog post you want the widget to display on.
9. Click the “Save” button to save the widget settings.
Now, the Text widget will only be displayed on the particular blog post that you selected in the “Conditional Widgets” settings.