To access data from TMDb, you need to create an account and obtain an API key. Sign up on the TMDb website, navigate to the API section in your account settings, and generate an API key. This key will authenticate your requests to the TMDb API.

Using your API key, construct HTTP requests to fetch the desired data from TMDb. For instance, if you want to get a list of popular movies, you can make a GET request to `https://api.themoviedb.org/3/movie/popular?api_key=YOUR_API_KEY`. Use a programming language like Python or JavaScript to automate these requests and handle the JSON responses.

Once you have retrieved the data, parse the JSON responses to extract the relevant information. This can be done using JSON parsing libraries available in your chosen programming language (e.g., `json` module in Python). Extract the fields you need, such as movie titles, release dates, and ratings.

If you haven't already, create a Google Cloud account and set up a project. Enable the Pub/Sub API in the Google Cloud Console. You may also need to set up billing information if this is your first time using GCP services.

In the Google Cloud Console, navigate to the Pub/Sub section and create a new topic. A topic is a named resource to which messages are sent by publishers. Note the name of your topic, as it will be used in subsequent steps to send messages.

Use a programming language with Google Cloud SDK support to publish messages to your Pub/Sub topic. For example, in Python, you can use the `google-cloud-pubsub` library. Initialize a publisher client and publish messages containing the parsed TMDb data to your topic. Ensure each message is correctly formatted as a JSON string.

Example in Python:
```python
from google.cloud import pubsub_v1

project_id = "your-project-id"
topic_id = "your-topic-id"

publisher = pubsub_v1.PublisherClient()
topic_path = publisher.topic_path(project_id, topic_id)

# Example movie data message
movie_data = {
"title": "Example Movie",
"release_date": "2023-01-01",
"rating": 8.5
}

# Publish the message
future = publisher.publish(topic_path, json.dumps(movie_data).encode("utf-8"))
print(f"Published message ID: {future.result()}")
```

After setting up the script, test it to ensure data is correctly being fetched from TMDb and published to your Pub/Sub topic. Use the Google Cloud Console to monitor your Pub/Sub topic and inspect the messages being received. Make any necessary adjustments to your script or configurations based on the results of your test.

By following these steps, you can move data from TMDb to Google Pub/Sub without using third-party connectors or integrations.