You can see how many times a bundle discount was applied (and other statistical info) in Bundler > Analytics. 

In addition to that, there are also two more ways to find orders with a bundle discount (this only works for our “Legacy bundles”): 

Option #1: 
To track performance of your bundles you have to turn on the option to tag the orders with the bundle names in Bundler > General Settings > Bundle info in orders and then filter the orders by bundle name in Shopify admin > Orders. 

Option #2: 
Navigate to Shopify admin > Orders page. Then click the Add filter +, select App and then select the Bundler - Product Bundles.