To make sure the app can display the bundle funnel popup, you have to add one of the products from the bundle to the cart, but at the same time, you must not have the entire bundle to the cart. 

And the products which are part of the desired bundle must not already be discounted by another bundle in the cart. 

If these conditions are fulfilled, then the funnel popup should show up. But please keep in mind that if you closed the popup in the past, then the app won't show the popup again for some time, so that your customers don't get annoyed with it.