How is the aws personalize search plugin work ?

We have catalog of products. We are using elastic search for searching the products. I got to know about the plugin (link below) to connect open search and personalize to rank the results.

According to personalize, items are products and items interactions will be view, click, purchase actions.

When we give search term to open search, it find the items and gives the items to personalize for ranking. This is my understanding. But I am not sure how the item id from open search will get mapped to input in personalize requests ? Can some one explain this data transfer back and forth between search and personalize.

Plugin link - https://docs.aws.amazon.com/personalize/latest/dg/personalize-opensearch.html