Adding example in user guide

Signed-off-by: Vacha Shah <vachshah@amazon.com>

USER_GUIDE.md

@@ -1,6 +1,9 @@
 - [User Guide](#user-guide)
-    - [Example](#example)
-    - [How to use IAMs as authentication method](#how-to-use-iams-as-authentication-method)
+	- [Example](#example)
+	- [How to use IAMs as authentication method](#how-to-use-iams-as-authentication-method)
+			- [AWS SDK V1](#aws-sdk-v1)
+			- [AWS SDK V2](#aws-sdk-v2)
+			- [AWS SDK V2 with OpenSearch Serverless](#aws-sdk-v2-with-opensearch-serverless)
 
 # User Guide
 
@@ -283,3 +286,91 @@ func main() {
 }
 
 ```
+
+#### AWS SDK V2 with OpenSearch Serverless
+
+AWS SDK V2 for Go can be used for Amazon OpenSearch Serverless. To create a client, please see the example below:
+
+```go
+package main
+
+import (
+	"context"
+	"log"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/config"
+	opensearch "github.com/opensearch-project/opensearch-go/v2"
+	opensearchapi "github.com/opensearch-project/opensearch-go/v2/opensearchapi"
+	requestsigner "github.com/opensearch-project/opensearch-go/v2/signer/awsv2"
+)
+
+const endpoint = "" // serverless collection endpoint
+
+func main() {
+	ctx := context.Background()
+
+	awsCfg, err := config.LoadDefaultConfig(ctx,
+		config.WithRegion("<AWS_REGION>"),
+		config.WithCredentialsProvider(
+			getCredentialProvider("<AWS_ACCESS_KEY>", "<AWS_SECRET_ACCESS_KEY>", "<AWS_SESSION_TOKEN>"),
+		),
+	)
+	if err != nil {
+		log.Fatal(err) // Do not log.fatal in a production ready app.
+	}
+
+	// Create an AWS request Signer and load AWS configuration using default config folder or env vars.
+	signer, err := requestsigner.NewSignerWithService(awsCfg, "aoss") // "aoss" for Amazon OpenSearch Serverless
+	if err != nil {
+		log.Fatal(err) // Do not log.fatal in a production ready app.
+	}
+
+	// Create an opensearch client and use the request-signer
+	client, err := opensearch.NewClient(opensearch.Config{
+		Addresses: []string{endpoint},
+		Signer:    signer,
+	})
+	if err != nil {
+		log.Fatal("client creation err", err)
+	}
+
+	IndexName = "go-test-index"
+
+	// Create an index with non-default settings.
+	createIndex := opensearchapi.IndicesCreateRequest{
+		Index: IndexName,
+	}
+	createIndexResponse, err := createIndex.Do(context.Background(), client)
+	if err != nil {
+		log.Println("Error ", err.Error())
+		log.Println("failed to create index ", err)
+		log.Fatal("create response body read err", err)
+	}
+	log.Println(createIndexResponse)
+
+	// Delete previously created index.
+	deleteIndex := opensearchapi.IndicesDeleteRequest{
+		Index: []string{IndexName},
+	}
+
+	deleteIndexResponse, err := deleteIndex.Do(context.Background(), client)
+	if err != nil {
+		log.Println("failed to delete index ", err)
+		log.Fatal("delete index response body read err", err)
+	}
+	log.Println("deleting index", deleteIndexResponse)
+}
+
+func getCredentialProvider(accessKey, secretAccessKey, token string) aws.CredentialsProviderFunc {
+	return func(ctx context.Context) (aws.Credentials, error) {
+		c := &aws.Credentials{
+			AccessKeyID:     accessKey,
+			SecretAccessKey: secretAccessKey,
+			SessionToken:    token,
+		}
+		return *c, nil
+	}
+}
+
+```