How to set default Lakehouse in the notebook programmatically?

Hi keataunooi 
Thanks for using Fabric Community.
To programmatically attach a lakehouse for a session level, you can use this below code in your notebook:

# Welcome to your new notebook
# Type here in the cell editor to add code!
%%configure
{
    "defaultLakehouse": {  # This overwrites the default lakehouse for current session
        "name": "your-lakehouse-name",
        #"id": "<(optional) lakehouse-id>",
        #"workspaceId": "<(optional) workspace-id-that-contains-the-lakehouse>" # Add workspace ID if it's from another workspace
    }
}

Hope this helps. Please let me know if you have any further questions.