Begin by accessing the Linnworks API. You will need API credentials, which include Application ID, Application Secret, and Token. You can obtain these by setting up an application in the Linnworks Developer Portal. Ensure you have the necessary permissions to access the data you want to export.

Use the credentials to authenticate your application. Send a POST request to the Linnworks authentication endpoint using your Application ID, Application Secret, and Token to receive an access token. This token will be used in subsequent API requests to access your data.

Determine the specific data you wish to export from Linnworks (e.g., inventory items, orders, etc.). Refer to the Linnworks API documentation to identify the correct API endpoints and parameters required to fetch this data.

Construct and send HTTP GET requests to the appropriate Linnworks API endpoints using the access token obtained earlier. Ensure your requests include any necessary parameters to filter or sort the data as needed. Capture the JSON response from each request, which will contain the data you need.

Once you receive the JSON response from the API, parse it to extract the relevant information. Depending on your programming language, use built-in JSON parsing libraries (such as `json` in Python or `JSON.parse` in JavaScript) to handle the response and structure it for your needs.

After parsing the data, format it into a JSON structure that suits your requirements. This may involve filtering unnecessary fields, restructuring the data, or combining multiple responses into a single JSON object or array.

Finally, write the formatted JSON data to a local file. Use file handling functions in your programming language to create and write to a file with a `.json` extension. Ensure you handle any potential errors during the file creation and writing process to avoid data loss.

By following these steps, you can effectively move data from Linnworks to a local JSON file without relying on third-party connectors or integrations.