Help with GCP permissions

I’m working on connecting my first Google Cloud Platform (GCP) database to Wix. I was able to follow all of the steps listed here[1] and have it successfully running (yay!). However, my permissions to the GCP data sets are read only. Not surprising as I did not create a PERMISSIONS secret with the permissions uploaded. With that said…How is this done? I can’t seem to find much luck “Googling” for such a result. I am brand new to some of this stuff so I need a template or some documentation on creating a permissions file in JSON. Any guidance? Thank you!!
[1] Velo: Integrate Your Google Cloud BigQuery Database with Your Wix Site | Help Center | Wix.com