The json import doesn't work either by import or paste in he grafana dashboard because of smart quotes. It is here in the docs:
Go to Grafana Dashboard accessible at localhost:3000, login as admin:admin. Import the grafana-twitter-scdf-analytics.json dashboard. You will see a dashboard similar to this:
To work around the problem I downloaded the json and did a search/replace of the quotes in emacs with normal quotes and the json paste worked fine.