We have a family PS4 which I set up as the primary user with parental controls etc and my two kids have sub accounts. My eldest has now bought himself his own PS4 for his room and I'm wondering how to get this set up for him. I still want parental controls and he will need to be able to link to our primary account to enable us to authorise funds when he wants to buy something. How do I set up this new PS4 to enable him to use his current PSN account?
You should be able to sign-in to the new PS4 with your son's existing PSN details (which should have been created on the Family PS4). Signing with the existing details will retain the trophies and other data, but you will have to setup any console-specific parental controls again (like Play time limits and age restrictions). You will also sign-in as the main (master) account holder in order to setup the parental controls.