[Samba] Configuring Samba as a file server to use AD authentication

[Kyle Manel]

Hello,

I am attempting to install Samba as a file server within an Active Directory domain to use the AD server for group authentication.
I have worked through various guides, but all leave me unable to authenticate into the samba shares using my organizations existing user groups in Active Directory.
I need the following configuration:

Share - users : description
Admin - Admin : This share is exclusive to its user group
Media - media users : This share is exclusive to its user group and the Admin group
Junk - all users : This share is accessible to everyone

There are 3 different user groups that will be using this server, Admin, Media and Everyone.

I have a Microsoft Active Directory Server (2012R2) operating as my AD server, and an Ubuntu server operating for Samba.

I would like:
users to be authenticated each access to the share,
the process of adding/removing users to be done by the AD server.