RAG implimentation

I have a large industry specifc dataset that I stored in opensearch, I then created embeddings for the indexes so I can use opensearch as my vector db to search knn story, I now what to ask the data questions using the OpenWebUi, currently everything is running in a kubernetes cluster I just need to add the feature to webui.

What do I use here? a function? a pipeline? I'm not really sure where to start all the tutorials don't seem to point me in the direction.