Begin by ensuring that your data is in a supported format for Snowflake ingestion. Snowflake supports several file formats such as CSV, JSON, Avro, Parquet, and ORC. Organize your data files in a directory structure that facilitates easy upload and management. Ensure that the files are properly formatted and free of errors to avoid issues during the loading process.

Gather all the data files you intend to upload into a directory on your local machine. This step is crucial as it organizes your data for efficient transfer to the Snowflake environment. Confirm that each file is complete and correctly formatted, as this will minimize potential errors during the upload process.

Use the SnowSQL command-line interface to upload files to a Snowflake stage. First, ensure that SnowSQL is installed and configured on your machine. Then, execute the `PUT` command in SnowSQL to transfer your data files to a designated Snowflake stage. For example:
```
PUT file:///local_path/to/datafile.csv @your_stage_name;
```
This command uploads your local files to a Snowflake internal stage, making them ready for loading into tables.

If you haven’t already created a table in Snowflake to hold the data, do so using the `CREATE TABLE` statement. Define the table schema to match the structure of your data files. For example:
```sql
CREATE TABLE your_table_name (
column1_name column1_datatype,
column2_name column2_datatype,
...
);
```
Ensure the data types and column names match those in your data files to avoid mismatch errors during the loading process.

Use the `COPY INTO` command to load data from the stage into your Snowflake table. This command reads the files from the stage and inserts the data into your table. For example:
```sql
COPY INTO your_table_name
FROM @your_stage_name
FILE_FORMAT = (TYPE = 'CSV' FIELD_OPTIONALLY_ENCLOSED_BY = '"')
ON_ERROR = 'CONTINUE';
```
Adjust the `FILE_FORMAT` and other options to match the specifics of your data files, ensuring a smooth and accurate load process.

After loading the data, perform validation checks to ensure the data has been loaded accurately and completely. Use `SELECT` queries to inspect a sample of the data and perform counts or checksums to verify data integrity. For example:
```sql
SELECT COUNT(*) FROM your_table_name;
```
This helps confirm that the number of records matches expectations and that data types align with your schema requirements.

Once you have verified the data load, clean up the staging area by removing files that are no longer needed. This can be done using the `REMOVE` command in Snowflake:
```sql
REMOVE @your_stage_name;
```
Clearing the stage ensures that it remains organized and avoids incurring unnecessary storage costs for files that have already been processed.
These steps should guide you through the process of moving data to Snowflake without relying on third-party tools, focusing on using native Snowflake features and utilities.