I need tutorial, too. but nothing was found

You can use Matter.framework to Commissioning. You will found example

You should Add EnableBluetoothCentralMatterClientDeveloperMode.mobileconfig from here

I have the same problem. I need to know the error code when the user explicitly cancels the pairing, but in many abnormal cases, this error returns code=1.

Here are some explanations https://developer.apple.com/forums/thread/757458

maybe you should paired by MatterSupport.framework first. Then use Matter.framework to pair. MatterSupport.framework will Share setup information to you.