I am new to Houdini. I'm following Peter Quints videos, the one on curves where he clicks on tool options “create in context” so you can add to an existing curve without creating a new curve node. I have hovered over everything I can see in viewport but nothing of its kind shows up. The video is from 2011 so did this get moved/changed or deleted? I've attached pic of the process in question.

That feature is still there. It is in the far right top corner of the Scene view tab. It is even the same icon as shown above. Make sure that the Tool Options bar hasn't been stowed. If you can't see it then click on the bar at the top of the scene view - it should unstop the too options.

Thank you Robert, yes it was hidden. I have it now. Thank you.