Improve readme example

Author: alexleventer

README.md

@@ -1,13 +1,21 @@
 # @datastax/astra-db-ts
 
+`astra-db-ts` is a TypeScript client for interacting with [DataStax Astra DB](https://astra.datastax.com/signup).
+
 ## Getting Started
 
 ```typescript
 import { AstraDB } from "@datastax/astra-db-ts";
 
-const { TOKEN, DATABASE_ID, REGION, COLLECTION_NAME } = process.env;
+const { TOKEN, DATABASE_ID, REGION, COLLECTION_NAME, ENDPOINT } = process.env;
 
 const astraDb = new AstraDB(TOKEN, DATABASE_ID, REGION);
+// or...
+// const astraDb = new AstraDB(TOKEN, ENDPOINT);
+
+// Create a collection
 const collection = await astraDb.collection(COLLECTION_NAME);
+
+// Return the number of documents in the collection
 const results = await collection.countDocuments();
 ```