Begin by logging into your EmailOctopus account. Navigate to the list or campaign whose data you want to export. Use the built-in export feature to download the data as a CSV file. This option is typically found in the list settings or campaign details section. Choose CSV as your format to ensure compatibility with DuckDB.

Open the exported CSV file using a spreadsheet application such as Microsoft Excel or Google Sheets. Verify the data's integrity by checking for any corrupted entries or missing fields. Make necessary corrections to ensure the data is clean and consistent. Save the CSV file once you have verified its accuracy.

If you haven't already, download and install DuckDB on your local machine. DuckDB is available for various operating systems, including Windows, macOS, and Linux. Follow the installation instructions provided on the DuckDB website to set it up correctly.

Open your terminal or command prompt. Launch DuckDB by typing `duckdb` to start the interactive shell. Create a new database by executing the command `CREATE DATABASE emailoctopus_data;`. This command initializes a new DuckDB database file where you'll store your imported data.

Define the structure of your data in DuckDB by creating a table that matches the columns of your CSV file. Use the `CREATE TABLE` SQL statement, specifying each column's name and type. For example:

```sql
CREATE TABLE email_data (
subscriber_id VARCHAR,
email VARCHAR,
first_name VARCHAR,
last_name VARCHAR,
signup_date DATE
);
```

Adjust the table schema to match the columns in your CSV file.

Use the `COPY` command in DuckDB to import the CSV data into your newly created table. Assuming your CSV file is stored in the same directory as DuckDB, execute the following command:

```sql
COPY email_data FROM 'your_file.csv' (FORMAT CSV, HEADER);
```

Replace `'your_file.csv'` with the actual path to your CSV file. The `HEADER` option tells DuckDB to ignore the first row of the CSV, treating it as column headers.

Once the import process is complete, verify that the data has been correctly imported into DuckDB. Run a simple `SELECT` query to view a few rows of data:

```sql
SELECT * FROM email_data LIMIT 10;
```

Check for any discrepancies or missing data. If everything appears correct, your data migration from EmailOctopus to DuckDB is now complete. Adjust queries as needed to suit your specific use case.

By following these steps, you can effectively transfer data from EmailOctopus to DuckDB without relying on third-party connectors or integrations.