When you create a connection and select a file, Sheetgo displays a list of files in your main Google Drive folder. Shared files (files created or owned by someone else, but shared with you) are stored in a separate part of Google Drive so they are not immediately visible, but there are three ways of finding them:
Use the Search bar and type the file or folder name. Sheetgo will look in both your main Google Drive folder and shared Google Drive folders.
Click on the Shared with me icon, this will show only the files and folder that have been sharing with you.
Add a shortcut from the "Shared with me" section of Google Drive, and send the shortcut to any part of your main Drive.
The shortcut will appear in your main Google Drive list (just like files created by you) but with a shortcut icon.