Login to https://squareadmin.grubbrr.com/ and go to Menu → Upsells. Click on Add New. There, you can choose the item that you want to upsell, the upsell price, and the items that you want your upsell to be connected to. When you are done, click the Save button to create the new upsell item. Finally, click the Tablet Icon on the top right corner to sync data to the kiosk. Now your upsell is live on your kiosk.