YITH WooCommerce Added to Cart Popup lets you open a popup window automatically every time you add a product to the cart. In the popup you can see a summary of all products in it, the total price, up-sells and cross-sells products and more.
The integration with YITH Frequently Bought Together will let the Cart popup open automatically whenever one or more products from the Frequently Bought Together section are added to the cart.
If both plugins are installed and activated, you will be able to enable a new option on the settings page of Added to Cart Popup plugin: YITH Plugins > Added to Cart Popup > Settings > Enable for “Frequently Bought Together” button.
If you add one or more products from the Frequently Bought Together section, the popup will open including all of them and any possible discount that had been set up through Frequently Bought Together plugin:
To read more about YITH Added to Cart plugin, please, refer to the plugin documentation here.