If you're running the latest version of flowforge and the agent, Your projects will have access to two context stores - memory & persistent.
These context stores are relative to where they are running. For example, when the project is running on a device, it uses the devices, memory, and file system.
The sample service expects you to use a service account with all the necessary permissions to access the opt/flowforge-device directory & any necessary Comms port permissions that you want the node-red project on the device to use.