Related Bundles are the bundles that are shown automatically by the app at the Cart page when a visitor adds product/s into the cart which matches the created bundles in the app.
Below image shows the cart page where a product Face Rose Bio Oil is added to the cart and app shows the bundles related to the product in the top area of cart page.
Settings for Related Bundles:
To do the settings for Related bundles
Go to main Settings > Cart Page > Related Bundles
With the Switch you can on/off the display of related bundles on the cart page and
Show number of related bundles on cart page allows you to give the count for related bundles you want to show on the cart page.