Begin by ensuring your IBM Db2 environment is correctly configured. Verify that you have the necessary permissions to access the database and export data. Confirm network settings to allow communication between the systems if they are on different networks.

Use the IBM Db2 export utility to extract data from your desired tables. This can be done using the command-line interface or through a SQL statement such as:
```sql
EXPORT TO 'data.csv' OF DEL MODIFIED BY NOCHARDEL SELECT FROM your_table_name;
```
This command exports data into a CSV file format, which is a widely supported data exchange format.

Once the data is exported, securely transfer the CSV file to a location accessible by your Databricks environment. This could be a cloud storage solution such as AWS S3, Azure Blob Storage, or a direct upload if your Databricks environment supports it. Use secure file transfer protocols like SCP or SFTP if transferring over a network.

Set up your Databricks Lakehouse environment to access the location where the CSV file is stored. This includes configuring necessary credentials and permissions for the storage service. For example, if using AWS S3, ensure IAM roles and bucket policies are set up correctly.

Use the Databricks interface to import the data from the storage location into Databricks. This can be done using a PySpark or Scala notebook with a command such as:
```python
df = spark.read.csv("path_to_your_csv_file", header=True, inferSchema=True)
```
This reads the CSV file into a Spark DataFrame, which can be manipulated and analyzed within Databricks.

Perform any necessary transformations on the data to fit the schema and needs of your Lakehouse environment. Use Spark SQL or DataFrame operations to clean and optimize data. For example, you might remove duplicates, rename columns, or change data types.

Finally, save the transformed data into a permanent table within Databricks Lakehouse. Use the following command to write the DataFrame to a Delta table:
```python
df.write.format("delta").saveAsTable("your_table_name")
```
This command saves the DataFrame in a Delta format, which supports ACID transactions and efficient storage, a key feature of Databricks Lakehouse.

By following these steps, you can efficiently move data from IBM Db2 to Databricks Lakehouse without relying on third-party connectors or integrations.