First, ensure you have a Google Cloud Project set up. If not, create one in the [Google Cloud Console](https://console.cloud.google.com/). Enable billing and make sure you have access to the necessary Google Cloud services like Google Cloud Storage (GCS) and Google Pub/Sub.

In your Google Cloud Project, enable the necessary APIs: Google Cloud Storage API and Google Pub/Sub API. You can do this from the APIs & Services section in the Google Cloud Console by searching for these APIs and enabling them.

Navigate to the Google Cloud Storage section in the Console and create a new bucket or use an existing one. Upload the data files you wish to transfer to Pub/Sub into this bucket. Ensure that the bucket permissions allow reading of the files you want to process.

In the Pub/Sub section of the Google Cloud Console, create a new topic that will be used to publish messages. This topic will hold the data coming from your GCS bucket. Make sure to note the topic's unique identifier, as it will be used in your script or application.

Go to the Cloud Functions section and create a new function. Configure this function to trigger whenever a new file is created in your GCS bucket. Set the event type to "Cloud Storage" and the event "Finalize/Create". This function will contain the logic to publish the file data to the Pub/Sub topic.

In the Cloud Function editor, write the code that reads the file from GCS and publishes its content to the Pub/Sub topic. Use the Google Cloud client libraries for Node.js, Python, or your preferred language. Make sure your code includes proper error handling and logging for debugging purposes.
Example in Python:
```python
import base64
from google.cloud import pubsub_v1
from google.cloud import storage
def gcs_to_pubsub(event, context):
# Initialize clients
storage_client = storage.Client()
pubsub_client = pubsub_v1.PublisherClient()
# Retrieve bucket and file information
bucket_name = event['bucket']
file_name = event['name']
# Access the file from the bucket
bucket = storage_client.get_bucket(bucket_name)
blob = bucket.blob(file_name)
file_data = blob.download_as_bytes()
# Specify the Pub/Sub topic
topic_path = pubsub_client.topic_path('your-project-id', 'your-topic-id')
# Publish the file data to the Pub/Sub topic
future = pubsub_client.publish(topic_path, data=file_data)
future.result() # Ensure the publish is complete
print(f'File {file_name} from {bucket_name} sent to {topic_path}.')
```

Deploy your Cloud Function with the appropriate settings and permissions. Ensure that the service account running the function has sufficient permissions to read from GCS and publish to Pub/Sub. After deployment, upload a new file to the GCS bucket and check the Pub/Sub topic to verify that the data is being successfully published. Monitor logs in the Cloud Functions section for any errors or issues.
By following these steps, you can move data from Google Cloud Storage to Google Pub/Sub using native Google Cloud services and tools, without the need for third-party connectors or integrations.