I want to use llama to create an AI

I want to use llama to create an AI chatbot for PDFs. I've tried to start with the documentation example but nothing.. i've understand how llama works but it cause openaiapikey error..how can i solve this?
i've copied this
// example.ts
import fs from "fs/promises";
import { Document, VectorStoreIndex } from "llamaindex";

async function main() {
// Load essay from abramov.txt in Node
const essay = await fs.readFile(
"node_modules/llamaindex/examples/abramov.txt",
"utf-8"
);

// Create Document object with essay
const document = new Document({ text: essay });

// Split text and create embeddings. Store them in a VectorStoreIndex
const index = await VectorStoreIndex.fromDocuments([document]);

// Query the index
const queryEngine = index.asQueryEngine();
const response = await queryEngine.query(
"What did the author do in college?"
);

// Output response
console.log(response.toString());
}

main();
AND THIS IS THE PROBLEM AuthenticationError: Incorrect API key provided: sk-pgr1k***NI0x.
right
what does it means?
export OPENAI_API_KEY="sk-......" # Replace with your key from https://platform.openai.com/account/api-keys
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where i have to put my OPENAI_API_KEY??
Please, if you can, help me