Please help understand what it means "Configure the billing account the project folder level in the resource hierarchy" statement. According to Architecting with Google Kubernetes Engine: Foundations Week 1 Introduction to Google Cloud, configuring the billing account is possible at the folder level.
However, according to Overview of Cloud Billing concepts, it should be at the project level.
The same coursera Billing section also mentions the billing is at project levels.
Link your billing account to one or more projects.Projects you don't link to any billing account can only use free Google Cloud services.Your billing account can be charged automatically and invoice every month, or at every threshold limit.

