You can get technical assistance for Application Design Center through Google Cloud support packages. You can report documentation issues by filing a bug.
Get a Google support package
Google Cloud offers different support packages to meet different needs, such as 24/7 coverage, phone support, and access to a technical support manager. For more information, see Cloud Customer Care.
File documentation bugs
To open a feedback form, from the App Design Center documentation, click Send feedback. Your comments are reviewed by the App Design Center team.