Begin by exporting the data you want to transfer from ClickHouse. You can use the `clickhouse-client` command-line tool to export data into a CSV format. For example:
```bash
clickhouse-client --query="SELECT * FROM your_table" --format CSV > data.csv
```
This command exports the entire table `your_table` into a CSV file named `data.csv`. Adjust the query as needed to select specific columns or rows.

Before importing data into Postgres, ensure that the destination database and table are properly set up to receive the data. Use the Postgres `psql` command-line tool to create the necessary table, ensuring that the schema matches the data structure of the ClickHouse export.
```sql
CREATE TABLE your_table (
column1 datatype,
column2 datatype,
...
);
```
Adjust the column names and data types to match those in your CSV file.

If your Postgres server is on a different machine, securely transfer the CSV file to the server. You can use tools like `scp` (Secure Copy Protocol) for this purpose:
```bash
scp data.csv user@postgres-server:/path/to/destination/
```
Replace `user`, `postgres-server`, and `/path/to/destination/` with the appropriate values for your setup.

Ensure the Postgres user has the necessary permissions to perform the data import. You may need to grant additional privileges if your user does not already have them:
```sql
GRANT INSERT ON your_table TO your_user;
```

Use the `COPY` command in Postgres to import the data from the CSV file into the target table. This can be done within the `psql` command-line tool:
```sql
COPY your_table FROM '/path/to/destination/data.csv' WITH (FORMAT CSV);
```
This command reads the CSV file and inserts its contents into `your_table`.

After the import, verify that the data has been correctly transferred by running some basic queries to check the count of rows and sample data. For example:
```sql
SELECT COUNT(*) FROM your_table;
SELECT * FROM your_table LIMIT 10;
```
Compare these results with your original data in ClickHouse to ensure accuracy.

Once you have verified the data transfer, clean up any temporary files, such as the CSV file, to free up space and maintain security:
```bash
rm /path/to/destination/data.csv
```
Ensure you do this on both the source and destination servers if applicable.
By following these steps, you will be able to successfully move data from ClickHouse to Postgres without the use of third-party connectors or integrations.