For a single worksheet you can use GSheets > File > Download As > Comma Separated Values (CSV)
Then you can load the gsheet with loadTable to a Table, or with loadStrings if for example you only have one column.
If you want to query the contents of a GSheet over the web then you would need to send network messages from your sketch using the Google Sheets API.
This is decidedly advanced. It might actually be much easier to have a sync client or automatic task to periodically download your full sheet and load the local copy.