First, log in to your MailerLite account and navigate to the section containing the data you wish to export, such as subscribers, campaigns, or reports. Use the export functionality provided by MailerLite to export this data in a CSV format. Ensure the exported file includes all necessary columns and data for your analysis.

Set up a local environment to handle the exported CSV files. This includes ensuring you have a secure location to store the files temporarily and software like Python or SQL client tools to assist with data processing and transfer. Make sure your environment has access to Snowflake.

Before uploading to Snowflake, clean and format the CSV data. This might involve removing any unwanted columns, checking for data inconsistencies, and ensuring that the data types are consistent with the Snowflake table schema. Use tools like Python (Pandas library) or a spreadsheet application for this task.

In your Snowflake account, create an internal stage where you will upload the CSV files. Use the Snowflake web interface or a SQL client to execute the following SQL command:
```sql
CREATE STAGE my_internal_stage;
```
This command sets up a temporary storage area within Snowflake for your CSV files.

Use Snowflake’s command-line interface, SnowSQL, to upload your cleaned CSV files to the internal stage. Execute the following command in your terminal:
```shell
snowsql -c my_connection -q "PUT file://path/to/your/exported_file.csv @my_internal_stage"
```
Replace `my_connection` with your SnowSQL connection configuration and `path/to/your/exported_file.csv` with the actual file path.

Define the structure of the table in Snowflake that will store the imported data. Use the Snowflake interface or a SQL client to execute a CREATE TABLE statement, ensuring the columns match the CSV headers:
```sql
CREATE TABLE my_table (
column1 datatype,
column2 datatype,
...
);
```

Finally, load the data from the internal stage into your Snowflake table. Execute the following SQL command to copy the data:
```sql
COPY INTO my_table
FROM @my_internal_stage/file_name.csv
FILE_FORMAT = (TYPE = 'CSV' FIELD_OPTIONALLY_ENCLOSED_BY = '"');
```
Ensure the file name is correct and that any file format options match the structure of your CSV file. Verify the data is correctly loaded by querying the table afterward.

By following these steps, you can seamlessly move data from MailerLite to Snowflake without third-party connectors or integrations.