I've looked for documentation on this, and I cannot find it (search fail?):  How do I do the equivalent of creating a button to launch a flow in lightning?

I know there is a new Flow component in Summer '17, but when I add it to my page, it tells me that there aren't any available flows.  I'm guessing it is because it is an auto-launched flow? 

So how can I add a button/action to let the user choose to fire it off? It requires 3 variables from the current record in order to run correctly.

Thanks!