Unity Mirror networking transport issue

Hi, I am trying to develop a small-scale MMO. I am using Unity 6000.0.38f1 and downloaded the most recent Mirror from asset store (states it supports unity 6000).

Both use namespace Mirror:

image

The NetworkManager component has the empty space for transport, but refuses to let me drag and drop a transport script into it; additionally, when I click to list out the available transports it is empty. Anyone have any idea how to move forward with this?

This is what the “help” documentation said; so with this step already not working I am stuck.