Shipmate deploys every environment in a new Google Cloud project. To organize these project and restrict Shipmate's access to your Google Cloud account you should create a folder.
Using the search field at the top of the Google Cloud Console, search for Manage Resources and click on the first result.
You should now see the Manage resources page.
Click on the button labeled Create folder at the top of the page.
Fill out the form that appears.
Finally, copy the ID of the folder you just created, as you will need to enter it in Shipmate as part of the last step in this guide.