Begin by accessing the Intercom API to extract the necessary data. First, ensure you have API access by generating an API key from your Intercom account. Use the API key to authenticate requests to Intercom's endpoints. Use tools like `curl` or a scripting language (e.g., Python with `requests` library) to fetch data. Make GET requests to the relevant Intercom endpoints (e.g., contacts, conversations) to retrieve JSON data.

Once you've extracted the data, you might need to transform it into a format suitable for ClickHouse. ClickHouse supports importing data in formats like CSV, TSV, JSONEachRow, etc. If your data from Intercom is in JSON, you might need to convert it to JSONEachRow or another supported format. This can be accomplished using scripting languages like Python to iterate over JSON objects and write them to a file in the desired format.

Before importing data, ensure your ClickHouse database is set up to receive it. Define tables in ClickHouse that match the structure of your data. Use the ClickHouse `CREATE TABLE` SQL statement to set up the schema, including defining appropriate data types for each column based on the structure of your data from Intercom.

Transfer the formatted data files to the server where ClickHouse is running. You can use secure file transfer methods such as `scp` or `rsync` to move files from your local machine to the ClickHouse server. Ensure the transferred files are placed in a directory accessible by the ClickHouse instance.

Use ClickHouse's `INSERT INTO ... FORMAT` command to import the data from the files into your ClickHouse tables. For example, if you have a CSV file, you would use a command like `INSERT INTO my_table FORMAT CSV` to load the data. Make sure the file paths and formats match what you prepared in previous steps.

After importing data, verify the data integrity by running queries in ClickHouse to ensure the import was successful. Check for the correct number of rows and examine sample data to confirm that it matches your expectations. This step helps ensure no data was lost or corrupted during the transfer process.

If you need to regularly update your ClickHouse database with new data from Intercom, automate the process. Write a script or cron job that periodically extracts new data from Intercom, transforms it, transfers it to the ClickHouse server, and imports it into the database. This can be done using shell scripts or automation tools like `cron` on Unix-based systems.

By following these steps, you can efficiently move data from Intercom to your ClickHouse warehouse without relying on third-party connectors or integrations.