Hi,
The createNewApp function has an optional parameter to allow you to pass an identifier for a template available on the appstore. So if you use the following:
client.platform().createNewApp(`NewApp-${Date.now()}`,`Description of App`,`ec936796-c0de-4ac9-bae8-60f08d6c55e2`);
It will create a new app using the blank app template available on the appstore.
Does this help?
Simon