had a look at the code, i think you almost got the index created correctly but the key step missing is vectorizing the data and store the embedding for semantic search. These steps are a little long, worth looking at the example here, it is a simple version of ingesting document and setuping index.
lots of more advanced examples here: https://github.com/Azure/azure-search-vector-samples/tree/main/demo-python
At a very high level: