Begin by exporting the required data from PostgreSQL. Use the `COPY` command to export data from a PostgreSQL table to a CSV file. This command outputs data into a plain text format, which is easily transferable.
```sql
COPY your_table TO '/path/to/your_data.csv' WITH (FORMAT CSV, HEADER);
```

Ensure that the CSV file is properly formatted. Check for any special characters, delimiters, or newline issues that might cause problems during the import process into Teradata. It's important that the data types in the CSV align with those expected in Teradata.

Move the CSV file to the Teradata server environment. This can be done using secure file transfer methods like SCP or SFTP if the systems are on separate machines. Ensure that the file permissions are set correctly to allow reading by the user that will perform the import.

Before importing the data, create the target table in Teradata with a structure that matches the CSV file. Use the `CREATE TABLE` statement, specifying appropriate data types for each column. This ensures that data is correctly interpreted upon import.
```sql
CREATE TABLE your_teradata_table (
column1 INTEGER,
column2 VARCHAR(255),
...
);
```

Use Teradata’s `TPT` (Teradata Parallel Transporter) or `FastLoad` utility to import the CSV data into the Teradata table. These utilities are designed for efficient bulk loading of data.
For example, using `FastLoad`:
```bash
fastload < my_fastload_script.txt
```
Ensure your script file is correctly configured to specify the CSV file location, table name, and the mapping of CSV columns to table columns.

After loading the data, validate that all records have been imported correctly. Perform counts and checks on key data points to ensure data integrity. Compare row counts between the PostgreSQL source and the Teradata target table.
```sql
SELECT COUNT() FROM your_teradata_table;
```

Once the data is confirmed to be imported correctly, apply any necessary indexes or optimization techniques on the Teradata table to improve query performance. This might include creating primary indexes or collecting statistics.
```sql
COLLECT STATISTICS ON your_teradata_table COLUMN (column_name);
```

By following these steps, you can effectively transfer data from PostgreSQL to Teradata without relying on third-party connectors, leveraging the capabilities of each database system.