To activate Simple UpSell, go to the "Apps" option on the Settings bar, and choose Simple UpSell
Click on "+New Offer" and enter a name for the offer.
Begin typing the name of the product the customer will have in their basket, and select it from the drop down. Then, do the same for the product that you want to upsell.
Then, create a title and content for the offer.
Choose the priority at which you would like to place the offer. Low will make it pop up less, high will make it pop up every time someone goes to check out.
Don't forget to save your offer!
On the main app settings page, you can publish and delete your offers.
For more information on the Simple Upsell Application view our Marketplace.