I'm working on the Build Flexible Apps with Visualforce Pages and Lightning Components badge, and am hitting some snags.

Snag 1 was creating a new playground. I know how to do it -- but the robots building the playground ran out of power and stalled the first time they tried to build one, and built a non-functional playground the second time (when the 'launch playground' button yields a Page Not Found error, you know those robots had problems), and the third time seemed to be the charm.

Until I started working on the steps.  They validate just fine, which is nice in a way.  But when the instructions say go to the Dreamhouse Lightning app and click on Data Import , then Initialize Sample Data -- and your click on Data Import yields a "This page isn't available in Salesforce Lightning or mobile app"  and then the directions say to click on leads and notice that it looks like Salesforce Classic, because it is -- except you get a notice saying the page is not available in Lightning...  despite supposedly being a custom Visualforce page that works in Lightning.  

Is a fourth playground the solution?  I really would like to see what this VF cutting and pasting I am doing does.