Use ldap or AD for authorization in other applications

[BlinCT]

Hello everyone.
The essence of my question is this: there are several services, nextcloud and jellyfin.
I would like, if possible, to take users from LDAP(better for me) or AD to use them. That is, the user goes to, for example, nextcloud.domain.com and uses for authorization the user created in nextcloud, passes verification in the authentik.
I would also like to do the same for jellyfin.
But I do not yet understand how possible this is, and how to do it.
Thank you for your understanding, I hope someone will advise me the necessary direction for the solution.