First, access the CommCare HQ platform and navigate to the "Data" section. Use the "Export Data" feature to extract the necessary data. Choose the appropriate data type (e.g., form data, case data) and configure the export settings as needed. Once configured, download the data, which is typically in CSV or Excel format.

Ensure your local environment is set up to handle potential data transformations or scripting. Install Python and the necessary libraries, such as `boto3` for AWS interactions and `pandas` for data manipulation. You can install these libraries using pip with the commands `pip install boto3 pandas`.

Depending on your requirements, you may need to transform the exported CommCare data. Use Python and libraries like `pandas` to read the data file and perform any necessary transformations (e.g., filtering, aggregating, or cleaning). Save the transformed data to a new file if modifications are needed before uploading.

Set up AWS credentials to allow your local environment to interact with your S3 bucket. This involves creating an IAM user with appropriate permissions for S3 access and downloading the access key and secret key. Store these credentials securely in the AWS credentials file located at `~/.aws/credentials` on your system. The file should look like this:

```
[default]
aws_access_key_id = YOUR_ACCESS_KEY
aws_secret_access_key = YOUR_SECRET_KEY
```

If you haven't already, create an S3 bucket in the AWS Management Console where you will upload your CommCare data. Make sure to note the bucket name and the region it's in, as you will need this information when configuring the upload script.

Develop a Python script using `boto3` to upload the data file to your S3 bucket. Below is a basic example of how such a script might look:

```python
import boto3

# Initialize a session using your credentials
session = boto3.Session(
aws_access_key_id='YOUR_ACCESS_KEY',
aws_secret_access_key='YOUR_SECRET_KEY',
region_name='YOUR_REGION'
)

# Initialize the S3 client
s3 = session.client('s3')

# Upload the file to S3
file_name = 'path_to_your_file.csv'
bucket_name = 'your_bucket_name'
object_name = 'desired_object_name_in_s3.csv'

try:
s3.upload_file(file_name, bucket_name, object_name)
print("Upload Successful")
except Exception as e:
print(f"Upload Failed: {e}")
```

Execute this script from your command line or IDE to upload the file.

After executing the upload script, verify that the file has been uploaded by checking the S3 bucket through the AWS Management Console. Ensure that the file is in the correct location and has the desired permissions. You may need to adjust the object’s permissions to allow for public access or to ensure that it's accessible to the appropriate users within your organization, depending on your use case.

By following these steps, you can transfer data from CommCare to S3 without relying on third-party connectors or integrations, maintaining full control over the process.