How to run peercoin in a private blockchain mode?

How to run peercoin in a private chainblock mode?
Well ,you know ,ethereum can run in a private blockchain mode and so it can run in my pc’s network.
So would you please tell me how to run peercoin in a private blockchain mode or in a testnet mode and not in a public mode?
I just want to study the peercoin ,thank you .

In “peercoin.conf” file, write: “testnet=1”