Upsells Overview
To start using PopupUpsell, access the Module Settings > Upsells and click Green Plus button on the top right-hand side.

This action will create your first Upsell and show you all the settings you can configure.
Upsell Settings
Configuring Upsell is simple. Start with filling the Upsell name.
The next step is enabling the Upsell status
Later, if you want to stop showing a Upsell, but want to keep its template, simply disable its status. This will not remove any of the Upsell settings.
The next step is to configure the Upsell showing on mobile, enable or disable the Upsell for mobile devices.
The next set of popup Width and Height.
Method
You can choose to show the popup on the specific products or categories.
Custom CSS
You can styling the popup content by adding the custom CSS code here.
Popup Content
This is the editor that allows you to add product or category shortcuts to appear in the popup. If you using the category shorcut, the popup will be showed 1 random product in that category.
To get the product ID, go to the Catalog > Products and hover the Edit button.
To get the category ID, go to the Catalog > Categories and hover the Edit button.
PopupUpsell Extension