I just added new products, but the app is not recognizing the products as available
After you create a new product Shopify has to send us its data, what, depending on the platform conditions, may take a from seconds to a couple of hours. Don't worry, the fresh data will be there rather sooner than later.
You can proceed with the configuration even if we don't have the product data (this is why the app only shows the product ID). Once we get the data, the configuration will be applied, no configuration will be lost.