Start by logging into your SurveyCTO account. Navigate to the "Export" section where you can download the data from your surveys. Choose the desired survey and export the data in a CSV format. Ensure that you have selected all necessary fields and that the data is clean and ready for processing.

Set up your local machine to handle the data transfer process. This involves having a functional database client or command line tool like ClickHouse's `clickhouse-client` installed. Ensure that you have access rights to upload data to your ClickHouse instance.

Using the ClickHouse command line tool, create a table that matches the structure of your SurveyCTO data. Connect to your ClickHouse server and use the `CREATE TABLE` statement. Ensure the data types of the columns in ClickHouse match the columns from your SurveyCTO CSV.

```sql
CREATE TABLE survey_data (
id UInt32,
name String,
response_date Date,
response_text String
) ENGINE = MergeTree()
ORDER BY id;
```

Use the `clickhouse-client` to upload your CSV data into the newly created table. You can do this via the command line by specifying the correct CSV file path and ensuring that the CSV format matches the table schema.

```bash
clickhouse-client --query="INSERT INTO survey_data FORMAT CSV" < /path/to/survey_data.csv
```

After the data transfer, it is crucial to validate that the data in ClickHouse matches your original data from SurveyCTO. You can perform a simple `SELECT` query to ensure that the number of records and sample data match expectations.

```sql
SELECT COUNT(*) FROM survey_data;
```

Once your data is in ClickHouse, you may want to optimize it for efficient querying. Consider creating additional indexes or partitions if necessary, depending on your query patterns and data size. This can be done by altering the table settings or using ClickHouse's `ALTER TABLE` commands.

```sql
ALTER TABLE survey_data ADD INDEX idx_name (name) TYPE minmax GRANULARITY 3;
```

If you need to regularly update your data, create a script that automates the export from SurveyCTO and the import into ClickHouse. This could be a bash script or a Python script using libraries like `pandas` for data manipulation. Schedule this script using cron jobs on a Unix-based system or Task Scheduler on Windows.

By following these steps, you can successfully transfer your data from SurveyCTO to a ClickHouse warehouse without relying on third-party connectors.