You just need to select a blank that will finish at the length you want. The chamber and muzzle end is like a regular blank but the center is turned down and wrapped in carbon.
Are you asking anything special? Or are you wanting a more general process explained to you?
If the later then read this https://rifleshooter.com/2013/03/chambering-a-barrel/
If youre asking about the earlier then still read it as its the same thing.