For Gist to gain access to your Google Sheet, you will need to make your spreadsheet public. Start by clicking “Share” on your Google Sheet.
Next, select “Advanced” in the lower right corner of the popup.
This will take you to the advanced sharing settings. From here, click the “Change…” link, next to the current privacy settings.
On the next screen, select the radio button next to “On - Anyone with the link”. Save your changes.
After you have saved your changes, copy the shareable URL. You will use this URL as the data source for your visualization. It should look similar to this: https://docs.google.com/spreadsheets/d/1Gt94htxLduEwcIhNrmI_Yep9HYS9Cc9lTwCsXvhh0Ts/edit?usp=sharing
Now let's add the Google Sheet as a data source in Gist. Navigate to the Visualizations tab in the Gist dashboard, click the “New Visualization” button, and enter a name for your new visualization. On the next screen, under "Select Your Data Source", select “Connect to a Google Sheet” from the option tiles.
Next, paste the URL we copied from the Google Sheet earlier into the text field, and click "Connect".
Finally, click "Save and Next" and your Google Sheet data will be uploaded into Gist.