This application uses Gnome's own Online Accounts interface, there is no need for any external connection to Google or the need to enter a password.
Whenever a change in files or directories is detected, it will automatically send these changes to the respective Google Drive folder. This way, your files will always be up to date in the cloud.
1. Connect your gmail on Online Accounts from Gnome Settings
2. Select the option "Files" to connect the gnome to your Google Drive
3. Open the GDriveSync app and select the path you want to monitore, type your mail and the name from the first directory of your Google Drive. And click on Save All.
4. Click to activate the Sync and Done.