fix(doc): fix instructions

Author: krokoko

samples/multimodal-rag/backend/README.md

@@ -43,7 +43,7 @@ git clone https://github.com/aws-samples/generative-ai-cdk-constructs-samples.gi
 Enter the backend directory
 
 ```shell
-cd samples/bedrock-bda-media-solution/backend
+cd samples/multimodal-rag/backend
 ```
 
 ### Create Python virtual environment

samples/multimodal-rag/frontend/README.md

@@ -37,7 +37,7 @@ Welcome to the demo frontend application. With this, you'll be able to upload an
 2. Enter the frontend directory
 
    ```shell
-   cd samples/bedrock-bda-media-solution/frontend
+   cd samples/multimodal-rag/frontend
    ```
 
 3. After successfully deploying your back-end stack, you can easily find the information required for the next step by inspecting to Amazon API Gateway and/or Amazon CloudFormation console.