Detailed Review Of Preparation

1. Linux Academy  Course by Matthew Ulasien

2. Official Google Guide - Dan Sullivan

3. GCP for Architects

4. Google Documentation online- overview of each service, security, limits/quotas, best practices

5. Whizlabs for Practice Test

Understand the basic concepts on Cloud Architecture Principles and Design Principles and map that to how its done by Google.

I have a background in Data Center Management due to that I already had a background to designing / architecting for  back-up, security, availablity and reliability. In addition to that I had led a migration to Private Cloud. These experience helped.