Set up your local environment by installing Python and necessary libraries. You will need:
- Python 3.x
- `pandas` library to read the Excel file.
- `google-cloud-pubsub` library to interact with Google Pub/Sub.
You can install these using pip:
```bash
pip install pandas google-cloud-pubsub
```

Log in to your Google Cloud Console and enable the Pub/Sub API for your project. Navigate to the API Library, search for "Pub/Sub API," and click "Enable."

In the Google Cloud Console, go to the Pub/Sub section and create a new topic. Note down the topic name as you will need it in your script. This topic will receive the messages (data) from the Excel file.

Create a service account in your Google Cloud Console for authentication. Assign it the "Pub/Sub Publisher" role. Download the JSON key file for this service account and save it securely on your local machine.

Use Python and pandas to read data from your Excel file. Here's a simple example:
```python
import pandas as pd

# Load the Excel file
df = pd.read_excel('your_file.xlsx') # Replace 'your_file.xlsx' with the path to your Excel file

# Convert DataFrame to a list of dictionaries
records = df.to_dict(orient='records')
```

Use the `google-cloud-pubsub` library to publish data to your Pub/Sub topic. Here is an example of how you can do this:
```python
from google.cloud import pubsub_v1
import json

# Set the path to your service account key
import os
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = 'path/to/your/service-account-key.json'

# Initialize a Publisher client
publisher = pubsub_v1.PublisherClient()
topic_path = publisher.topic_path('your-project-id', 'your-topic-name') # Replace with your project ID and topic name

# Publish each record to the topic
for record in records:
data = json.dumps(record).encode('utf-8') # Convert the record to a JSON string
publisher.publish(topic_path, data)
```

Check if the data has been successfully published to your Pub/Sub topic. You can do this by:
- Navigating to the Pub/Sub section in Google Cloud Console.
- Viewing the "Messages" tab under your topic to ensure messages are being received.

By following these steps, you should be able to move data from an Excel file to Google Pub/Sub without the need for third-party connectors or integrations. Make sure you have the necessary permissions and your Google Cloud project is correctly set up.