spark not defined using VSCode Synapse Extension

I am attempting to work on a pyspark notebook locally using VS Code and the Microsoft Synapse extension.

I installed all dependencies as described in the documentation for the extension. I've connected to a workspace and opened my notebook. However, when attempting to execute my first block I am seeing that "spark" is not defined. I've attempted all runtime interpreters with no success:

I even attempted to install pyspark manually in the terminal so I could create a new session, but then pyspark is also unknown. I've been doing allot of searching around trying to figure out how all this is supposed to work but with no luck. Just calling out in the dark here, wondering if anyone might be able to assist. 

Thank you.