Begin by reviewing the Convex Dev API documentation to understand how to interact with the data. Identify the endpoints you will need to access the data you want to export. Note any authentication requirements and data formats provided by the API.

Prepare your local environment for the task. Ensure you have a suitable programming language and environment set up, such as Python, Node.js, or another language capable of making HTTP requests. Install any necessary libraries for making HTTP requests and handling data.

Use the Convex Dev API to authenticate and retrieve the data. Write a script to make an authenticated HTTP GET request to the relevant API endpoint. Handle any required authentication tokens or keys as specified in the documentation. Parse the response data, typically in JSON format.

Once you have retrieved the data, transform it into a format suitable for CSV export. This might involve extracting specific fields, flattening nested structures, or formatting dates and numbers. Use libraries available in your programming environment to manipulate and prepare the data.

Define the structure of your CSV file. Specify the headers based on the data fields you extracted in the previous step. Create a list of lists or a similar structure where each sublist represents a row in your CSV file.

Use your programming environment's built-in libraries to write the transformed data to a CSV file. In Python, for instance, you can use the `csv` module to open a file in write mode and use the `csv.writer` object to write the headers and data rows.

After exporting, verify the CSV file to ensure data integrity. Open the file with a spreadsheet program or a text editor to check for correct formatting, data completeness, and accuracy. If necessary, iterate on your script to fix any data issues or format inconsistencies.
By following these steps, you can successfully move data from Convex Dev to a local CSV file without relying on third-party connectors or integrations.