Getting "Must enable billing on Google Cloud Project"
Solution 1:
Some Google Cloud Services are free and you can use it right away, but some others require to have an associated billing account although they are free, just in case you exceed the free usage allowed.
You have to enable billing account on the Google Cloud Project.
If you don't have one, first create a billing account:
https://cloud.google.com/billing/docs/how-to/manage-billing-account
Then, associate the project to the billing account:
https://cloud.google.com/billing/docs/how-to/modify-project