First, ensure that your IBM Db2 database is up and running. Verify that you have the necessary permissions to access and export the data. You will need to know the database connection details such as the hostname, port, database name, username, and password.

If you haven't already, install the Db2 Command Line Processor (CLP) or any Db2 client tool on your machine. This will allow you to execute SQL queries and export data from your Db2 database. You can download the Db2 client from IBM's website.

Use the Db2 CLP to export the data you need. You can use the `EXPORT` command to output data into a CSV or another text-based format. For example:
```
EXPORT TO '/path/to/data.csv' OF DEL MODIFIED BY NOCHARDEL
SELECT * FROM your_table;
```
This command will export the entire table to a CSV file at the specified path.

Weaviate requires data to be in a specific JSON format. Write a script (using Python, Node.js, etc.) to convert the CSV data into JSON objects. Ensure that each object aligns with the schema you plan to use in Weaviate. Include necessary fields and data types.

Set up your Weaviate instance. This can be done locally using Docker or on a cloud provider. Make sure you have the necessary API keys and access tokens if your instance is secured. Define your schema in Weaviate according to the data structure you are importing.

Use Weaviate's RESTful API to import data. Write a script to post each JSON object to Weaviate. Here's a simplified example using Python and the `requests` library:
```python
import requests
import json

url = "http://localhost:8080/v1/objects"
headers = {"Content-Type": "application/json"}

with open('/path/to/data.json', 'r') as file:
data = json.load(file)
for item in data:
response = requests.post(url, headers=headers, json=item)
if response.status_code != 200:
print("Failed to import:", response.text)
```
Adjust the URL and port according to your Weaviate setup.

After importing the data, verify that all entries are correctly loaded into Weaviate. Use the Weaviate console or API to query the data and ensure that it matches what was exported from Db2. Check for any errors or discrepancies and repeat the import process if necessary.

By following these steps, you can successfully migrate your data from IBM Db2 to Weaviate without relying on third-party connectors or integrations.