In your VPC demo you say to create a New Project. When I try to create a new project it requires a Parent Organization or folder. There is no way to create a new project, this is the error: "You must select a parent organization or folder." Selecting BROWSE, there is no organization listed. I will just proceed with the default project.
Resource Manager is one of the services that is unavailable to Sandbox users, probably because the tear-down script might miss resources that you could create. See https://help.acloud.guru/hc/en-us/articles/360001389276