First, log into your Typeform account and navigate to the form containing the data you want to export. Use Typeform's built-in export feature to download the form responses. Typically, you can export the data as a CSV file. Ensure that you have access to all the necessary fields required for migration.

Prepare the PostgreSQL database where you want to import the data. This involves setting up a database instance and creating the necessary tables to match the structure of the data exported from Typeform. Use a PostgreSQL client like `psql` or a graphical interface like pgAdmin to create the tables with appropriate data types and constraints.

Open the exported CSV file using a spreadsheet application such as Excel or a text editor. Review the data to ensure there are no inconsistencies or errors. This step may involve correcting data types, removing duplicates, and handling any missing or malformed data. Save the cleaned data in the same CSV format.

Develop a script to transform the CSV data into SQL insert statements. You can use a programming language like Python with libraries such as `pandas` to read and manipulate the CSV data. The script should generate SQL commands that match the structure of your PostgreSQL tables. For example, loop through each row in the CSV file and construct an `INSERT INTO` statement for each record.

Use your preferred programming language or SQL client to connect to the PostgreSQL database. Execute the SQL insert statements generated in the previous step. If you are using Python, the `psycopg2` library is a good choice for establishing a connection and executing SQL commands. Ensure you handle exceptions and errors during this process to avoid data corruption.

After importing the data, verify its integrity by comparing a subset of the data in PostgreSQL with the original data in the CSV file. Perform spot checks to ensure that all records have been transferred accurately and that the data types and values are consistent. Run SQL queries to check for any anomalies or discrepancies.

Once you've verified the data import is successful, consider automating the entire process for future data transfers. You can schedule the export, transformation, and import steps using a task scheduler (like cron jobs on Unix-based systems or Task Scheduler on Windows) and a script that encapsulates all the steps. This will streamline the process and reduce manual effort for future data transfers.

This guide provides a practical approach to transferring data from Typeform to PostgreSQL without relying on third-party integrations, ensuring full control over the process.