Open WeUpsell Dashboard
Go to Templates
Click on the "Checkout Product Offer" from the "Checkout" section
Customize the Widget
Click on the product image to select the product you want to add on the checkout page.
You can also apply a discount if desired.
Note: This is a one-time offer and will not be available to the customer later.
Save and Publish the Template
Click on Save and Exit to store your changes.
Click on Save and Publish to make the offer live.
Final Look: