Instructions for this app and a CSV template can be found on its Github repository.
This app runs completely in your browser - none of your data is sent outside of your own computer. This also means that the data will not be saved if you close or reload the page.
Graph Code: Copy this text and save it as a html file you can link to:
iFrame Code: Copy this code into your page and replace "YOUR_URL_HERE" with the link to the html file you saved: