I am having trouble finding this information.
I am finding lots of stuff on communicating between a lightning component and Visualforce page when the Visualforce page is embedded inside the lightning component as an iframe, which involves doing postMessages and what not.
However, my situation is that I have a Visualforce page that I put a lightning component on.
I want the user to fill out the form in the lightning component, then click 'OK', and be able to get that info back on the Visualforce page. However, I am unsure how you perform this kind of communication. The Lightning component is not in an iframe when you embed it in a Visualforce page, so doing some complicated postMessage should not be necessary.