To add an upsell:
Go to the bundle editor.
Open the Upsells tab.
Click Add Upsell.
Then link your Shopify product to this upsell.
To remove an upsell:
Click on the upsell you want to delete.
Click Delete Upsell.
Important: once deleted, the upsell cannot be recovered.
If you run into any issues, contact MoonBundles support.