To begin, log into your Mailchimp account and navigate to the Lists or Audiences dashboard. Select the audience you want to export. Click on the "Export Audience" option, which will generate a .csv or .xls file containing the data. Download and save this file to your local system.

Open the exported file using a spreadsheet application like Microsoft Excel or Google Sheets. Review the data to ensure it is clean and consistent. Check for any missing values, incorrect formats, or unnecessary columns, and make necessary adjustments. Save the cleaned data in a .csv format, as this is typically easiest for import into databases.

Ensure that TiDB is properly installed and set up on your server. You can download TiDB from the official website and follow the installation instructions specific to your operating system. Verify that TiDB is running correctly by connecting to it using a MySQL client or command-line interface.

Use a MySQL client to connect to your TiDB instance. Determine the structure of the table you need based on the data you exported from Mailchimp. Use SQL commands to create a table with appropriate column names and data types that match the data from the .csv file. For example:
```sql
CREATE TABLE mailchimp_data (
id INT PRIMARY KEY,
email VARCHAR(255),
first_name VARCHAR(100),
last_name VARCHAR(100),
... // Additional columns as needed
);
```

Use the LOAD DATA INFILE command to import your .csv data into the newly created table in TiDB. Make sure the .csv file is accessible to the TiDB server. The command will look something like this:
```sql
LOAD DATA LOCAL INFILE '/path/to/your/data.csv'
INTO TABLE mailchimp_data
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
IGNORE 1 ROWS;
```
Adjust the file path and options as necessary to match your file structure and format.

After importing the data, run a series of SELECT queries to verify that the data has been correctly imported. Check for the number of rows, completeness of data in each column, and any discrepancies with the original data from Mailchimp. If any issues are found, address them by re-importing specific rows or adjusting the data.

For future data transfers, consider writing a script (using a language like Python or Bash) that automates the export, cleaning, and import processes. This script can streamline data movement and reduce manual effort. Schedule this script to run at regular intervals using a task scheduler like cron (Linux) or Task Scheduler (Windows).

By following these steps, you can effectively move data from Mailchimp to TiDB without relying on third-party connectors or integrations.