To make your Google Docs spreadsheet visible to Neonto's server, you must share it with the following user:
This email address is not a real person, but a so-called "service account" that represents Neonto Cloud. (When sharing your Google Sheet, uncheck the 'Notify' box -- this service account doesn't care about email notifications.)
If you want your app to be able to write into the spreadsheet, you should give Edit permission when sharing.
The first row of each sheet is the header, it provides the column names.
The Google Sheets interface supports only lowercase letters and dashes for column names, so other characters will be stripped when importing to Neonto Studio and your app. For example, a column named "Hello World!" will become "helloworld". You should keep this in mind when naming your columns. (This applies only to the header row; your data in all the other rows can of course contain any letters.)
Google Sheets doesn't support images directly. Instead you can put image URLs in a cell. However the column name must have the prefix "img-", otherwise Neonto Studio won't know that this URL should be loaded as an image!
The "img-" prefix is removed by Neonto Studio when it imports a column. For example, if your Google Sheets column is named "img-profilepicture", the column in Neonto will be called simply "profilepicture".
You can store your images on any service that makes them visible on the web, for example Imgur or Dropbox. To get the URL for an image, just right-click in your web browser and choose "Copy image link" (or similar).
Once you've shared the sheet, add it to the list of known sheets here. Enter the sheet's URL in the "Add" field above. You can also choose a short identifier for it (this is just for your own reference).