To begin, you need to access the Amazon Ads API to retrieve the required data. First, ensure you have the necessary credentials and permissions. Create or use an existing AWS account, then generate API keys from the Amazon Advertising Console. Use these keys to authenticate your requests. Refer to Amazon Ads API documentation for specific endpoints and parameters required to query the desired data.

Write a custom script in a programming language of your choice (e.g., Python, Java) to call the Amazon Ads API. This script should be capable of sending HTTP requests to the API, handling authentication, and receiving JSON or CSV formatted responses. Use libraries such as `requests` in Python to facilitate HTTP requests and responses. Ensure your script can handle pagination if the data set is large.

After extracting the data, transform it into a format suitable for Elasticsearch. This may involve cleaning the data, converting it to JSON format, and structuring it according to your Elasticsearch index mapping. Use scripting logic to filter, aggregate, or modify data fields as required. Ensure the transformed data adheres to Elasticsearch’s indexing requirements.

Set up your Elasticsearch environment if you haven't already. This involves installing Elasticsearch on your local machine or setting up an instance on a cloud service such as AWS, Azure, or Google Cloud. Configure your Elasticsearch instance to accept incoming data. Define the appropriate index and mapping structure to hold the data from Amazon Ads.

Create a script to upload data to Elasticsearch using its Bulk API. This script should read the transformed data and prepare it in the format required by the Bulk API, which typically involves alternating lines of metadata and data. Ensure your script handles potential errors and retries uploads if necessary. Use libraries such as `elasticsearch-py` in Python to facilitate this process.

Execute your bulk upload script to transfer the transformed data into your Elasticsearch instance. Monitor the process to ensure data integrity and completeness. Check Elasticsearch logs and use its built-in tools to verify that data has been indexed correctly. Address any errors that may arise, such as mapping conflicts or data type issues.

Once the data is loaded, verify its accuracy by running queries in Elasticsearch. Use Kibana or another visualization tool if available to inspect the data. Test different query scenarios to ensure the data is correctly indexed and can be retrieved as expected. Perform any additional indexing or mapping adjustments based on query results to optimize performance and data accessibility.

By following these steps, you can manually move data from Amazon Ads to Elasticsearch without relying on third-party connectors or integrations.