.

app.py

@@ -16,6 +16,14 @@ import os
 DESCRIPTION = """\
 # RAG - MongoDB Atlas Vector Search & OpenAI
 This app is designed to provide a simple chat where to improve the answer from OpenAI with private information located in MongoDB Atlas cluster.<br>
+
+# Prerequisites:
+ create a free DB called "langchain_demo" and a collection called "collection_of_text_blobs" in MongoDB Atlas (https://cloud.mongodb.com). After that, you have two options:
+ 
+ **option1**) execute locally "load_data.py" to create new documents and their embeddings in MongoDB
+ **option2**) import the JSON file "langchain_demo.collection_of_text_blobs.json"
+
+# Dataset
 The JSON documents in MongoDB looks like:
 ```
 {