When using the add-on for the first time, you should open the settings dialog, and pick your Google Drive™ folder with templates (or create one.)
If you are a Google Workspace™ domain administrator, you can create a template folder for all of your domain as follows:
Create a group createfromtemplate-admins@yourdomain.com,
Add your own email address to this group,
Create a new folder named "Templates (yourdomain.com)" and share it with everyone in your domain (with view rights only),
Add template files to this folder.
See terms and privacy policy.