Need Storyline block to talk to RISE to continue

You don't need a "finish" button. The "must complete the block above" CONTINUE button will automatically enable when the user completes the Storyline block. Completion is based on the Tracking setting when you publish the Storyline project to Review 360. 

For example, if it's a linear set of slides, you could track via viewing all of the slides. 

Another option: track via a "Complete course" trigger that runs on the last slide (or at whatever point you'd consider the Storyline part completed). Here's more info about that:  Primer: Storyline-block completions in Rise | E-Learning Heroes 

For future reference, this Exchange Best Practices section is for general questions about eLearning. You’re asking how to do something in the software. That type of question is a better fit in the Discuss Articulate Products section of the website. That's where those of us who regularly answer questions about how to use the software spend more of our time. And that's where more folks go to search for answers specifically related to Storyline, Rise, and other parts of Articulate 360.