Begin by installing the Google Cloud SDK on your local machine. This will provide the necessary tools to interact with Google Cloud services. Follow the installation instructions for your operating system from the [Google Cloud SDK documentation](https://cloud.google.com/sdk/docs/install).

Once the SDK is installed, configure it to use your Google Cloud project. Use the `gcloud init` command to set up your project and authenticate your account. Ensure that the Pub/Sub API is enabled in your Google Cloud Console.

In your Google Cloud project, create a Pub/Sub topic where you will publish your data. Use the following command:
```bash
gcloud pubsub topics create YOUR_TOPIC_NAME
```
Replace `YOUR_TOPIC_NAME` with the desired name for your topic.

Set up an SFTP client on your local machine or server where you will retrieve the data. You can use command-line tools like `sftp` or a scriptable library in a programming language of your choice (e.g., Python's `paramiko` library) to connect to the SFTP server.

Using your established SFTP connection, download the data files you need. You can automate this process with a script that periodically checks for new files and downloads them to a local directory. Here's a basic example using the `sftp` command:
```bash
sftp user@host:/remote/path/to/data /local/path/to/data
```

Write a script to read the downloaded data and publish it to your Google Pub/Sub topic. If you're using Python, you can employ the `google-cloud-pubsub` library to publish messages. First, install the library:
```bash
pip install google-cloud-pubsub
```
Then, use the following sample script:
```python
from google.cloud import pubsub_v1
# Initialize a Publisher client
publisher = pubsub_v1.PublisherClient()
topic_path = publisher.topic_path('YOUR_PROJECT_ID', 'YOUR_TOPIC_NAME')
# Read and publish data
def publish_data(file_path):
with open(file_path, 'rb') as file:
data = file.read()
publisher.publish(topic_path, data)
publish_data('/local/path/to/data')
```

To ensure continuous data movement, automate the entire workflow using a cron job or a similar scheduling tool. This will periodically trigger your script to fetch new data from the SFTP server and publish it to Pub/Sub. For example, set up a cron job like this:
```bash
*/30 * * * * /path/to/your/script.sh
```
This example runs the script every 30 minutes. Adjust the timing and script path as needed.
Follow these steps to securely and efficiently move data from SFTP to Google Pub/Sub without relying on third-party connectors or integrations.