How can I set up the Xbox One so that my son does not play Fortnite under my Account / Gamer Tag but under his own Account / Gamer Tag?

Until now, I always have to log in under my father's account so that my son, Fortnite, can play. There's no game under his account. But I would like him to play it under his account so that I can limit my time via screen time. Do I have to set this directly s.der Xbox under Settings? If I go under my account but I see no menu item under which I can make such a setting.

Or I can adjust this under https://account.microsoft.com/...y/settings, but I can't find where I can adjust it.

Normally you can set it directly on the box. Think you can link Acc's… That's extra for family members who will have the same games and apps as you with your Acc.

What is an ACC?

Account sorry